URBANA 


ILLINOIS  STATE  GEOLOGICAL  SURVEY 


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STATE  OF  ILLINOIS 

STATE  GEOLOGICAL  SURVEY 

FRANK  W.  DEWOLF.  Director 


BULLETIN  No.  23 


BIENNIAL  REPORT  FOR  1911  AND  1912 


ADMINISTRATIVE  REPORT 

AND 

EGONOMIG  AND  GEOLOGIGAL  PAPERS 


CERTAIN  REPORTS  IN  COOPERATION^  WITH  U.  S.  GEOLOGICAL  SURVEY 


PRINTED  BY  AUTHORITY  OF  THE   STATE  OF  ILLINOIS 


ILLINOIS  STATE  GEOLOGICAL  SURVEY 

UNIVERSITY  OF  ILLINOIS 

URBANA 

1917 


55T 


STATE  GEOLOGICAL  COMMISSION 


Frank  O.  Lowden,  Chairman 
Governor  of  Illinois 

Thomas  C.  Chamberlin,  Vice-Chairman 

Edmund  J.  James,  Secretary 
President  of  the  University  of  Illinois 


Frank  W.  DeWolf,  Director 
Fred  H.  Kay,  Asst.  State  Geologist 


LETTER  OF  TRANSMITTAL 


State  Geological  Survey 
University  of  Illinois,  March  12,  1917. 
Governor  Frank  O.  Lozvden,  Chairman,  and  Members  of  the  Geological 
Commission, 

Gentlemen :  I  submit  herewith  my  administrative  report  for  the 
biennium  ended  June  30,  1913,  and  recommend  that  it  be  printed  as 
Bulletin  No.  23.  The  financial  statements  in  the  report  have  previously 
been  submitted  to  the  Commission,  but  are  now  offered  for  printing  as  a 
public  record.  Similarly  the  accompanying  miscellaneous  papers  of  econ- 
omic interest  have  to  some  extent  already  been  issued  as  preliminary  ex- 
tracts from  Bulletin  23  at  a  time  when  congestion  in  printing  made  it  im- 
practicable to  publish  the  entire  volume. 

Very  respectfully, 

Frank  W.  DeWolf,  Director. 


(7) 


CONTENTS 

PAGE 

Administrative  Report,  by  F.  W.  DeWolf 11 

Mineral  Statistics  for  Illinois  in  1911  and  1912,  by  Helen  J. 

Skewes   25 

Oil  and  Gas  in  Colchester  and  Macomb  Quadrangles,  by 

Henry  Hinds 45 

Plymouth  Oil  Field,  by  Raymond  S.  Blatchley 51 

Geology  of  La  Salle  and  Hennepin  Quadrangles,  by  G.  H. 

Cady  55 

Stratigraphy  and  Paleontology  of  the  Alexandrian  Series 

in  Illinois  and  Missouri,  by  T.  E.  Savage 67 


(9) 


ADMINISTRATIVE  REPORT  FROM  JULY  1,  1911 

TO  JUNE  30,  1913 

By  F.  W.  DeWolf 


OUTLINE 

PAGE 

Introduction    11 

General   statement    11 

Organization  and  personnel    11 

Cooperation     14 

Geologic   section    14 

Stratigraphy    14 

Coal     " 14 

Oil  and  gas  15 

Clay     15 

Drainage   work    16 

Educational  bulletins   16 

Mineral  statistics    16 

Bureau  of  information  16 

Topographic  and  drainage  sections    17 

Publications    21 

Expenditures    22 

PLATE 
I.  Map  showing  progress  of  topographic  surveys   16 

TABLES 

1.  Progress  of  field  work  by  the  topographic  and  drainage  sections  for  fiscal  years, 

1912  and  1913   18 

2.  Total  expenditures  July  1,  1911,  to  June  30,  1913 22 

Introduction 
general  statement 
The  increasing  development  of  the  natural  resources  of  Illinois  makes 
necessary   a   gradual   broadening   of   the   Survey's   activities.      Coal   and 
petroleum  continue  to  hold  a  large  share  of  attention. 

Detailed  statistics  for  the  calendar  years  of  1911  and  1912  appear 
in  this  bulletin. 

ORGANIZATION    AND    PERSONNEL 

The  organization  of  the  Survey  remained  the  same  as  before  and 
included   a  general  office   and   three   technical   sections — geologic,   topo- 

(11) 


12  P.FKNNIAL   REPORT 

graphic,  and  drainage — besides  the  Mine  Rescue  Service,  which  was 
maintained  under  cooperation  at  Urbana.  The  geologic  section  was  ad- 
ministered by  F.  W.  DeWolf,  Director,  and  in  his  absence  by  Fred  H. 
Kay,  who  was  appointed  Assistant  State  Geologist  in  1911.  The  topo- 
graphic section  was  in  general  charge  of  R.  B.  Marshall,  Chief  Geog- 
rapher, and  in  immediate  charge  of  W.  H.  Herron,  Geographer  of  the 
Central  Division  for  the  U.  S.  Geological  Survey.  The  drainage  section 
was  supervised  by  Mr.  Herron  and  the  director.  Cooperative  work  was 
further  increased  by  the  establishment  of  the  Illinois  Coal  Mining  In- 
vestigations by  an  agreement  between  the  State  Geological  Survey,  the 
U.  S.  Bureau  of  Mines,  and  the  Department  of  Mining  Engineering, 
University  of  Illinois. 

Mrs.  C.  S.  Hyatt  acted  as  chief  clerk  from  July  1,  1911,  until  Decem- 
ber 6,  1913,  when  Miss  C.  IT.  Thory  was  appointed  to  fill  the  vacancy 
caused  by  her  resigation.  The  chief  clerk  was  assisted  by  Miss  Blanche 
Fowler,  as  stenographer  and  clerk.  Professors  Salisbury  and  Grant 
served  as  consulting  geologists  and  Professors  Parr  and  Bartow  as  con- 
sulting chemists.  Professor  A.  V.  Bleininger,  Consulting  Ceramist,  with 
R.  T.  Stull,  Ceramist,  continued  in  general  charge  of  the  clay  studies. 

Professors  Weller,  Savage,  and  J.  A.  Udden  have  given  part-time 
service  to  the  Survey  as  geologists.  G.  H.  Cady  was  employed  tempor- 
arily on  the  geology  of  the  La  Salle-Hennepin  quadrangles  and  the  New 
Haven- West  Frankfort  quadrangles.  R.  S.  Blatchley  with  assistants 
continued  studies  in  the  oil  fields  of  the  State.  L.  G.  Donnelly  and  C.  O. 
Sauer  made  field  studies  for  educational  bulletins  under  the  direction  of 
Professor  Salisbury.  Mining  study  required  the  services  of  Mr.  Kay, 
with  Mr.  K.  D.  White  as  assistant,  and  a  number  of  chemists  under  the 
general  direction  of  Professor  Parr.  Coal  analysis  and  various  chemical 
studies  were  carried  on  by  J.  M.  Lindgren  and  D.  F.  McFarland,  chem- 
ists, under  the  general  direction  of  Professor  Parr.  They  were  assisted 
by  J.  F.  Kohout,  F.  H.  Whittum,  L.  T.  Fairhall,  C.  W.  Sievert,  and  S. 
C.  Taylor.    C.  C.  Wriley  and  C.  W.  Smith  acted  as  draftsmen. 

A  number  of  other  men  served  for  short  periods  of  time  in  the  field 
and  in  the  office.     The  organization  of  the  Survey  was  as  follows : 

COMMISSIONERS 

Governor  C.  S.  Deneen,  Chairman  until  January  1,  1913 
Governor  E.  F.  Dunne,  Chairman 
Professor  T.  C.  Chamberlin,  Vice  Chairman 
President  E.  J.  James,  Secretary 


ADMINISTRATIVE  REPORT 

ADMINISTRATIVE  WORK 
F.  W.   DeWolf,  Director 
Fred  H.  Kay,  Assistant  State  Geologist 
C.  S.  Hyatt,  Chief  Clerk,  resigned 
C.  H.  Thory,  Chief  Clerk 

GEOLOGICAL  SECTION 

R.  D.  Salisbury,  Consulting  Geologist 
U.  S.  Grant,  Consulting  Geologist 
S.  W.  Parr,  Consulting  Chemist 
Edward  Bartow,  Consulting  Chemist 

A.  V.  Bleininger,  Consulting  Ceramist 

F.  W.  DeWolf,  Geologist 
H.  H.  Barrows,  Geologist 
Stuart  Weller,  Geologist 
T.  E.  Savage,  Geologist 
W.   S.  Bayley,  Geologist 
J.  A.  Udden,  Geologist 
Fred  H.  Kay,  Geologist 

R.  S.  Blatchley,  Assistant  Geologist 

G.  H.  Cady,  Assistant  Geologist 
K.  D.  White,  Assistant  Geologist 

C.  O.   Sauer,  Assistant  Geologist 
L.  C.  Donnelly,  Assistant  Geologist 
G.  H.  Cox,  Assistant  Geologist 

E.  W.  Shaw,  Assistant  Geologist 
R.  T.  Stull,  Ceramist 

J.  M.  Lindgren,  Chemist 

D.  F.  McFarland,   Chemist 

F.  H.  Whittum,  Analyst 
S.  C.  Taylor,  Analyst 

J.  T.  Kohout,  Analyst 

G.  Simpson,  Analyst 
C.  W.  Sievert,  Analyst 
L.  T.  Fairhall,  Analyst 

M.  G.  Mehl,  Field  Assistant 
Svante  Udden,  Field  Assistant 
S.  T.  Wallage,  Field  Assistant 

C.  S.  Corbett,  Field  Assistant 

D.  C.  Thompson,  Field  Assistant 
C.  S.  Ross,  Field  Assistant 

B.  H.  Schockel,  Field  Assistant 
Howard  Ferguson,  Office  Assistant 
Wilber  H.   Ponder,   Office  Assistant 
V.  J.  Ingold,  Office  Assistant 
Naomi  Doub,   Office  Assistant 

O.  F.  Brooks,  Office  Assistant 
R.   S.   Scholl,  Office  Assistant 
Harry  Almond,  Office  Assistant 


14  BIENNIAL   REPORT 


COOPERATION 


Formal  cooperation  with  the  U.  S.  Geological  Survey  has  been 
maintained  as  before  in  topographic  work,  in  geological  surveys  of  quad- 
rangle areas,  and  in  the  collection  of  mineral  statistics.  Surveys  of  over- 
flowed lands  were  carried  on  as  usual  in  cooperation  with  the  U.  S. 
Geological  Survey  and  the  Rivers  and  Lakes  Commission.  An  extensive 
chemical  study  of  Illinois  coals  was  carried  on  in  cooperation  with  the 
Department  of  Applied  Chemistry,  University  of  Illinois. 

Formal  cooperation  has  also  been  maintained  between  the  State 
Geological  Survey,  the  Department  of  Mining  Engineering  of  the  Univer- 
sity of  Illinois,  and  the  U.  S.  Bureau  of  Mines. 

To  the  numerous  firms  and  individuals  throughout  the  State  who 
have  shown  generous  cooperation  in  furnishing  drill  records  and  other 
information,  hearty  acknowledgment  is  due. 

Geologic  Section 
stratigraphy 

A  strong  effort  was  made  to  secure  records  of  all  new  drilling  in 
the  State.  The  manuscript  for  Dr.  Udden's  report  on  the  examination 
of  well  samples  from  35  deep  wells  was  submitted.  Work  was  completed 
on  the  Alexandrian  formations  by  Professor  Savage,  and  a  report  was 
submitted  for  publication.  Professor  Weller,  with  assistants,  spent  con- 
siderable time  in  southwestern  Illinois  completing  his  studies  on  the 
Chester  formations.  He  also  submitted  the  manuscript  for  his  mono- 
graph on  the  Mississippian  brachiopods. 

General  stratigraphic  studies  were  carried  on  in  the  following  quad- 
rangles :  Hennepin,  La  Salle,  Hardinville,  Sumner,  and  Baldwin  by  the 
State,  and  in  the  Centralia,  Colchester,  Macomb,  and  special  areas  by  the 
United  States. 

COAL 

The  Forty-seventh  General  Assembly  of  the  State  of  Illinois,  with 
a  view  of  conserving  the  lives  of  the  mine  workers  in  the  mineral  re- 
sources of  the  State,  authorized  an  investigation  of  the  coal  resources  and 
mining  practices  of  Illinois  by  the  State  Geological  Survey  in  cooperation 
with  the  Department  of  Mining  Engineering  of  the  University  of  Illinois 
and  the  United  States  Bureau  of  Mines.  A  cooperative  agreement  was 
approved  by  the  Secretary  of  the  Interior  and  by  representatives  of  the 
State  of  Illinois. 

Under  this  agreement  Mr.  Kay,  assisted  by  Mr.  K.  D.  White,  spent 
a  large  amount  of  time  in  the  detailed  investigation  of  the  coal  resources 


ADMINISTRATIVE  REPORT  15 

of  the  State.  About  100  typical  mines  were  examined  in  detail,  and 
material  was  collected  looking  toward  the  publication  of  reports  on  each 
of  eight  districts,  covering  the  entire  Illinois  field.  Office  work  was  begun 
on  the  reports  for  two  of  these  districts. 

.  The  Survey  also  carried  on  an  exhaustive  chemical  study  of  Illinois 
coals  from  samples  collected  in  the  100  typical  mines  selected.  The 
chemical  work  was  done  by  Mr.  J.  M.  Lindgren  and  assistants,  under 
the  general  supervision  of  Professor  S.  W.  Parr  of  the  Department  of 
Applied  Chemistry,  University  of  Illinois.  During  the  sampling  cam- 
paign incident  to  this  study  new  methods  of  sampling  were  devised,  and 
the  result  of  the  entire  campaign  will  be  a  distinct  contribution  to  our 
knowledge  of  Illinois  coals. 

Detailed  studies  of  the  coal  resources  of  La  Salle,  Hennepin,  Canton, 
Galatia,  Sumner,  Hardinville,  New  Haven,  and  West  Frankfort  quad- 
rangles were  continued  by  Messrs.  Grant,  Cady,  Savage,  Udden,  and 
various  assistants. 

OIL  AND  GAS 

Mr.  Blatchley  has  spent  considerable  time  in  the  field  and  in  the  prep- 
aration of  his  detailed  report  on  the  geology  of  the  main  oil  fields  of 
Illinois.  The  manuscript  for  this  report  was  submitted  to  the  printer  in 
November,  1912. 

After  the  completion  of  the  Sumner  and  Hardinville  topographic 
maps  Mr.  Blatchley  continued  to  collect  material  in  the  area  looking 
toward  the  publication  of  a  geological  folio  in  cooperation  with  the  U.  S. 
Geological  Survey.  The  stratigraphic  work  on  these  quadrangles  was 
done  by  Professor  Savage. 

In  the  fall  of  1911  Mr.  Kay  spent  two  weeks  in  the  Carlinville  area 
mapping  the  Carlinville  field,  running  levels  to  all  of  the  wells,  and  secur- 
ing logs  for  a  report  which  was  published  in  Extract  from  Bulletin  20. 
This  extract  contains  also  a  report  on  the  Carlyle  field  and  surrounding 
territory  which  was  prepared  by  Mr.  E.  W.  Shaw  of  the  U.  S.  Geological 
Survey  in  cooperation  with  the  State  Geological  Survey. 

CLAY 

In  connection  with  the  Coal  Mining  Investigations  the  geologists 
representing  the  Survey  have  collected  a  number  of  roof  shale  and  floor 
clay  samples  from  representative  mines  in  the  State  and  these  samples 
have  been  submitted  to  Ceramics  Department  of  the  University  of  Illinois 
for  testing. 


16  BIENNIAL  REPORT 


DRAINAGE    WORK 


The  Commission  recommended  last  summer  that  we  prepare  and 
publish  a  plan  for  reclamation  of  the  overflowed  lands  in  the  Embarrass 
Valley,  inasmuch  as  the  maps  which  we  had  submitted  to  the  Rivers  and 
Lakes  Commission  were  not  being  utilized  because  of  lack  of  funds. 
Accordingly  the  Director  arranged  for  the  work  to  be  done  by  the  Har- 
man  Engineering  Company  and  the  maps  to  be  engraved  from  the  bal- 
ance of  our  appropriation.  The  report  is  now  finished  for  early  distri- 
bution. The  Spoon  River  maps  are  awaiting  engineering  study,  and  the 
Saline  River  survey  lacks  completion.  Our  supply  of  maps  of  the  Kas- 
kaskia  and  Big  Muddy  valleys  is  exhausted  and  should  be  replenished. 

EDUCATIONAL    BULLETINS 

Mr  Sauer  continued  office  work  on  his  report  on  the  upper  Illinois 
Valley,  and  his  manuscript  was  submitted  for  publication.  The  congested 
condition  of  the  State  printer's  office  would  not  permit  of  publication 
during  the  biennium.  It  is  expected  that  the  manuscript  for  the  report 
on  the  Kaskaskia  Valley  will  be  submitted  shortly.  All  of  this  work  has 
been  carried  on  under  the  direction  of  Professor  R.  D.  Salisbury  of  the 
University  of  Chicago. 

MINERAL    STATISTICS 

The  Survey  continued  to  cooperate  with  the  U.  S.  Geological  Sur- 
vey in  the  collection  of  mineral  statistics.  Mr.  Cady,  with  assistants, 
spent  considerable  time  in  the  collection  of  this  material.  The  totals  for 
1910  and  1911  are  given  on  a  later  page. 

BUREAU    OF    INFORMATION 

The  Survey  maintains  a  bureau  of  information  for  the  convenience 
of  inquirers  about  mineral  resources  of  Illinois.  Requests  are  received 
in  great  numbers  both  from  inside  and  outside  the  State.  When  possible 
a  bulletin  containing  the  desired  information  is  mailed.  Frequently,  how- 
ever, it  is  necessary  to  make  special  study  and  to  reply  by  letter  at  some 
length.  Many  requests  for  the  identification  of  minerals  are  received 
and  answered  promptly ;  others  for  analysis  of  specimens  are,  for  the 
most  part,  necessarily  refused.  It  has  been  found  that  the  collection  of 
a  representative  sample  of  a  material,  and  the  investigation  of  its  favorable 
occurrence  for  development,  is  quite  as  essential  and  requires  expert 
advice,  just  as  does  chemical  analysis.  As  a  rule,  therefore,  unless  a  rep- 
resentative of  the  Survey  investigates  and  samples  a  mineral  deposit,  an 
analysis  at  public  expense  is  not  justified,  particularly  because  otherwise 


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ADMINISTRATIVE  REPORT  17 

Survey  funds  would  be  seriously  depleted  by  work  which  frequently  is 
of  no  permanent  value.  Preliminary  examinations  and  opinions  as  to 
probable  value  of  minerals  are  always  cheerfully  given. 

Topographic  and  Drainage  Sections 

In  accordance  with  the  cooperative  agreement  signed  May  25,  1911. 
by  George  Otis  Smith,  Director,  for  the  United  States  Geological  Survey, 
and  by  Charles  S.  Deneen,  Chairman  of  the  State  Geological  Commis- 
sion, and  Frank  W.  DeWolf,  Director  of  the  State  Geological  Survey, 
August  10,  1911.  for  the  State  of  Illinois,  the  Federal  and  State  surveys 
each  allotted  $10,000  for  cooperative  topographic  surveys  in  the  State  of 
Illinois  during  the  fiscal  year  beginning  May  25,  1911,  and  ending  June 
30,  1912;  $8,000  was  allotted  by  each  for  the  year  July  1,  1912,  to  June 
30,  1913. 

Table  1  is  a  summary  of  the  field  and  office  work  accomplished  dur- 
ing the  period  from  July  1,  1911,  to  June  30,  1913.  under  the  general 
direction  of  R.  B.  Marshall,  Chief  Geographer,  and  under  the  immediate 
supervision  of  W.  H.  Herron,  Geographer  of  the  Central  Division.  The 
work  from  May  25  to  June  30,  1911,  was  reported  in  the  results  accom- 
plished during  the  fiscal  year  1910-11. 

The  allotment  of  $3,750  for  overflowed  lands  made  by  the  State  for 
the  fiscal  year,  1912,  was  met  by  an  allotment  of  $1,250  by  the  Federal 
Survey.  Under  this  L.  L.  Lee  and  J.  B.  Leavitt  completed  the  survey 
of  the  Spoon  River  project,  in  Fulton  County,  the  area  mapped  being  26 
square  miles.  The  survey  of  the  Embarrass  River  project,  in  Jasper  and 
Cumberland  counties,  was  completed  by  Messrs.  Lee  and  Leavitt  and  H. 
W.  Peabody,  the  area  mapped  being  24  square  miles.  This  work  was 
for  publication  on  the  scale  of  1 :24,000,  with  a  contour  interval  of  5  feet. 
For  the  control  of  the  Spoon  River  project  Mr.  Leavitt  ran  33  miles  of 
primary  levels  and  established  10  permanent  bench  marks.  For  the  con- 
trol of  the  Embarrass  River  project  R.  G.  Clinite  ran  27  miles  of  primary 
levels  and  established  18  permanent  bench  marks.  For  the  control  of 
the  Saline  River  project,  in  Saline,  Gallatin,  Williamson,  and  Hardin 
counties,  Air.  Clinite  ran  120  miles  of  primary  levels  and  established  35 
permanent  bench  marks,  and  J.  R.  Ellis  ran  164  miles  of  primary  traverse 
and  set  14  permanent  marks.  No  allotment  for  overflowed  lands  was 
made  by  the  State  or  Federal  surveys  for  the  fiscal  vear  1913. 


18 


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ADMINISTRATIVE  REPORT  21 


Publications 


During  the  biennium  the  following  bulletins  were  issued : 
Bulletin  17,  Portland  cement   resources,  by  A.   V.   Bleininger. 
Bulletin  18,  Sand-lime  brick,  by  S.  W.  Parr  and  T.  R.  Ernest. 
Bulletin  19,  Geography  of  the  Wheaton  area,  by  A.  C.  Trowbridge. 
Extracts   from  Bulletin  20.     The  Carlyle  oil  field  and  surrounding  territory, 

by  E.  W.  Shaw ;  and  the  Carlinville  oil  and  gas  field,  by  Fred  H.  Kay. 
Bulletin  22,  Oil  in  Crawford  and  Lawrence  counties,  by  R.   S.  Blatchley,  has 

been  in  press  for  several  months. 
Bulletin  506,  Geology  of  the  Peoria  quadrangle,  by  J.  A.  Udden,  U.  S.  Geol. 

Survey  in  cooperation  with  State  Survey. 

Other  reports  awaiting  attention  are,  Lead  and  zinc,  by  G.  H.  Cox; 
Deep  borings  in  Illinois,  by  J.  A.  Udden ;  an  educational  bulletin  on  the 
Galena  region,  by  A.  C.  Trowbridge,  E.  W.  Shaw,  and  B.  H.  Schockel ; 
and  two  year  books  containing  miscellaneous  papers. 

Professor  Weller's  monograph  on  the  Mississippian  brachiopods  is 
yet  imprinted  and  seems  to  require  special  Survey  funds  to  bear  the 
expense  for  illustrations  and  special  binding. 

The  base  map  of  Illinois  was  published  in  1911,  and  the  geological 
map  on  the  same  base  was  distributed  early  in  1913. 

The  distribution  of  these  reports  so  as  to  prevent  waste,  and  yet 
make  them  most  widely  available,  has  been  in  itself  a  considerable  task. 
It  was  thought  that  the  interests  of  all  concerned  would  be  best  met  if 
500  copies  of  each  report  were  reserved  for  sale  at  the  cost  of  printing, 
the  receipts  from  the  sales  being  turned  into  the  State  treasury.  This 
makes  it  possible  for  libraries  to  complete  their  sets  and  for  persons 
having  real  need  for  any  of  the  volumes  to  obtain  the  earlier  ones  at 
small  cost.  The  remainder  of  the  edition  is  distributed  by  the  Survey 
and  the  Secretary  of  State  to  institutions  and  individuals  making  applica- 
tion for  them,  or  is  exchanged  with  other  Surveys  or  publishing  organ- 
izations. 


22 


BIENNIAL  REPORT 


EXPENDITURES 

The  total  expenditures  from  July  1,  1911,  to  June  30,  1913,  were  as 
follows : 

Table  2. — Total  expenditures  July  1,  1911,  to  June  30,  1913 


General  appropriation — 

Balance  on  hand  July  1,  1911 

Appropriation  July  1,  1911   

Appropriation  July  1,   1912    

Total  available    

Expenditures  July  1,  1911  to  June  30,  1913— 

Salary  and  expenses  of  administration   

Clerical  help  and  general  offices  expenses 

Postage  for  distribution  of  bulletins 

Oil  investigations    

Coal  investigations   (exclusive  of  mining  study) 
Cooperative    geological    surveys    (quadrangles)  . . 

General  stratigraphic  studies   

Water  resources  investigations  

Clay  resources  investigations    

Geological  surveys   (quadrangles)    

Educational  series   

Statistics     

Studies  of  lead  and  zinc  

Maps    

Topographic   surveys    

Balance  available  July  1,  1913  

Special  appropriation  for  coal  mining  study — 

Appropriation  July  1,  1911 

Appropriation  July  1,  1912 

Total  available    

Expenditures  July  1,  1911  to  June  30,  1913 — 

Coal  resources    

Chemical  work  on  coals   

Laboratory  equipment  and  maintenance 

Office  supplies  and  equipment  

Field  equipment 

Administration,  clerical  help,  and  drafting  

Telephone,  telegraph,  express,  and  freight 

Postage   

Balance  available  July  1,  1913   


$  1,865.92 
25,000.00 
25,000.00 


$  8,864.39 

7,001.18 

776.14 

2,599.42 

317.90 

6,014.75 

1,679.11 

275.68 

24.37 

2,182.25 

505.17 

792.44 

165.75 

972.50 

18,958.13 


$  4,500.00 
4,500.00 


$  4,456.97 
2,309.35 
577.24 
301.73 
226.05 
938.97 
117.47 
30.00 


$51,865.92 


51,129.18 


$     736.74 


9,000.00 


8,957.78 


42.22 


ADMINISTRATIVE  REPORT 


23 


Table  2. — Total  expenditures  July  1,  1911,  to  June  30,  1913 — Concluded 


Special  appropriation  for  survey  and  study  of  overflowed 
lands- 
Balance  on  hand  July  1,  1911   

Appropriation  July  1,  1911   

Total  available    

Expenditures  July  1,  1911  to  June  30,  1913 

Balance  available  July  1,  1913  


Preparation  of  illustrations  and  printing — 

Balance  on  hand  July  1,  1911   

Appropriation  July  1,  1911 

Appropriation  July  1,  1912 


Total  available   

Expenditures  July  1,  1911  to  June  30,  1913 

Balance  available  July  1,  1913 , 


$     686.29 
7,500.00 


$  528.11 
2,500.00 
2,500.00 


$   8,186.29 

7,689.81 

$      496.48 


$   5,528.11 
5,524.28 


3.83 


MINERAL  RESOURCES  IN  ILLINOIS 
IN  1911  AND  1912 

By  Helen  J.  Skewes 


OUTLINE 

PAGE 

Introduction    26 

Acknowledgments     26 

Review  of  mineral  resources 26 

Coal     29 

Coke    32 

Pig  iron   32 

Petroleum    33 

Natural  gas 36 

Gasoline   37 

Clay-working  industries   38 

Clay     38 

Clay  products    38 

Stone    39 

Sandstone    39 

Limestone    39 

Lime    40 

Cement  41 

Sand  and  gravel   41 

Fluorspar 41 

Mineral  water    42 

Silica     42 

Pyrite  and  sulphuric  acid  43 

Lead,  zinc,  and  silver 43 

Mineral  paints   44 

ILLUSTRATION 

FIGURE 

1.     Average  yearly  production  of  coal  in  Illinois  by  5-year  periods  since  1853 

in  short  tons 28 

TABLES 

3.  Output  and  value  of  mineral  products  in  Illinois,   1910-1912 27 

4.  Coal  production  of  Illinois  in  1911  and  1912,  by  counties,  in  short  tons  30 

5.  Statistics  of  the  manufacture  of  coke  in  Illinois,  1909-1912 32 

6.  Statistics  of  pig  iron  marketed  in  Illinois,  1910-1912 33 


(25) 


26  BIENNIAL   REPORT 

7.  Marketed   production   in   barrels    and    value   of   petroleum    in    Illinois,       page 

1889-1912 34 

8.  Fluctuation  in  prices  of  Illinois  petroleum  per  barrel,   1910-1912 34 

9.  Number  of  wells  completed  in  Illinois  by  counties  and  the  total  and 

average  daily  production  of  new  wells,  1910-1912 • 35 

10.  Record  of  natural  gas  industry  in  Illinois,  1910-1912 36 

11.  Depth  and  gas  pressure  of  wells  in  Illinois  by  counties,  1910-1912....  36 

12.  Production  in  short  tons  and  value  of  clay  mined  and  marketed  in  Illi- 

nois,  1910-1912    38 

13.  Clay  products  in  Illinois,  1910-1912 39 

14.  Value  of  production  of  limestone  in  Illinois  according  to  uses,  1910-1912  40 

15.  Lime  burned  in  Illinois,  1910-1912 40 

16.  Portland  cement  industry  in  Illinois,   1910-1912 41 

17.  Production  in  short  tons   and  values  of  different  kinds  of   sand  and 

gravel  in  Illinois,  1910-1912 41 

18.  Production  in  short  tons  and  value  of  fluorspar  in  Illinois,   1910-1912  42 

19.  Production  in  gallons  and  value  of  mineral  water  in  Illinois,  1910-1912  42 

20.  Value  of  tripoli  mined  in  Illinois,  1910-1912 42 

21.  Production  in  long  tons  and  value  of  pyrite  mined  in  Illinois,  1910-1912  43 

22.  Tenor  of  lead  and  zinc  ore  and  concentrates  produced  in  Illinois,  1911 

and  1912   44 

23.  Production  and  value  of  lead,  zinc,  and  silver  in  Illinois,  1910-1912 44 


INTRODUCTION 

Acknowledgments 

The  mineral  statistics  for  Illinois  in  1911  and  1912  were  collected  by 
the  U.  S.  Geological  Survey  and  Illinois  State  Geological  Survey  in  coop- 
eration. The  figures  presented  are  the  result  of  compilation  and  tabula- 
tion by  the  Federal  Survey. 

Review  of  Mineral  Resources 

A  comparison  of  the  total  values  of  mineral  products  by  states,  exclu- 
sive of  pig  iron,  gave  Illinois  second  rank  in  1911  and  third  in  1912, 
having  been  preceded  by  Pennsylvania  in  the  former  year  and  by  Pennsyl- 
vania and  West  Virginia  the  latter.  In  both  years  this  State  produced 
6.3  per  cent  of  the  total  value  for  the  country,  exclusive  of  pig  iron. 

During  1911  and  1912  Illinois  stood  first  in  output  of  fluorspar; 
second  in  value  of  coal,  though  third  in  quantity ;  second  in  tripoli  or 
silica ;  third  in  petroleum  and  pig  iron ;  fourth  in  coke,  clay  products,  and 
in  sand  and  gravel ;  fifth  in  cement ;  and  seventh  in  stone.  Table  3 
presents  a  summary  of  the  entire  mineral  production  for  Illinois  in  1910, 
1911.  and  1912. 


MINERAL  RESOURCES   IN   1911   AND   1912 


27 


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28 


BIENNIAL   REPORT 


i 


MINERAL  RESOURCES   IN   1911   AND    1912  29 

COAL 

The  coal-mining  industry  in  Illinois  has  grown  very  rapidly  the  last 
30  years.  Figure  1  shows  the  average  yearly  production  for  each  five- 
year  period  since  1853.  Commercial  mining  began  about  1833  when  St. 
Louis  was  furnished  with  coal  from  small  mines  in  St.  Clair  County,  an 
area  that  developed  rapidly  and  has  always  held  a  high  rank  amongst 
the  coal-producing  counties.  The  La  Salle  area  developed  very  soon  after 
the  completion  of  the  Illinois  and  Michigan  Canal  and  supplied  Chicago 
with  fuel.  With  the  building  of  railroads  other  parts  of  Illinois  opened 
mines,  until  now  the  area  of  most  recent  development  and  interest  is 
the  Franklin-Williamson  county  district  which  promises  to  grow  to 
tremendous  proportion.  The  coal  of  this  part  of  the  State  is  of  high 
grade  and  of  good  thickness. 

In  1911  and  1912  Illinois  ranked  third  as  a  coal-producing  State, 
having  been  preceded  by  Pennsylvania  and  West  Virginia.  In  total  out- 
put of  coal  during  the  history  of  the  industry,  a  rank  of  second  has  been 
maintained  since  1866.  A  comparison  of  values  of  coal  for  each  of  these 
two  years  gives  Illinois  second  place,  as  our  coal  sells  at  a  higher  price 
than  the  West  Virginia  coal ;  Illinois  operators  are  favored  with  large 
consuming  markets  close  at  hand  where  a  slightly  higher  price  per  ton 
is  more  desirable  than  the  tremendous  transportation  expenses  from  more 
distant  fields. 

In  1911  a  new  record  in  production  was  established,  the  tonnage 
having  increased  16.9  per  cent  over  the  previous  year  and  the  value  13.6 
per  cent.  In  spite  of  the  increased  wages  paid  as  a  result  of  the  big 
strike  of  1910,  the  average  price  per  ton  fell  from  $1.14  to  $1.11.  Whereas 
the  output  of  the  Eastern  States  was  seriously  affected  by  the  depression 
in  the  iron  and  steel  industry,  coal  mining  in  Illinois  was  unaffected,  as 
our  coals  are  non-coking  and  therefore  not  used  in  that  way.  Of  the 
102  counties  in  Illinois,  51  reported  an  output  of  coal  in  1911.  In 
decreasing  order  of  tonnage  for  those  counties  exceeding  three  million 
short  tons  they  are  Williamson,  Sangamon,  Macoupin,  St.  Clair,  Saline, 
Franklin,  Vermilion,  and  Madison.  Sixteen  counties  produced  more 
than  a  million  tons. 

In  1912  another  record  in  output  was  made,  the  increase  over  the 
previous  year  having  been  11.6  per  cent  in  quantity  and  18.1  per  cent  in 
value.  The  average  price  per  ton  increased  from  $1.11  in  1911  to  $1.17 
in  1912.  The  leading  counties  were  in  decreasing  order  Williamson, 
Sangamon,  Macoupin,  St.  Clair,  Franklin,  Saline,  and  Madison.  The 
only  changes  in  order  are  the  relative  positions  of  Franklin  and  Saline. 


30 


BIENNIAL  REPORT 


Franklin  County  has  shown  a  marked  yearly  increase  from  the  beginning 
of  its  history  of  production  in  1903. 

Table  4  presents  the  detailed  statistics  for  coal  production  by  counties 
in  1911  and  1912. 

Table  4. — Coal  production  of  Illinois  in  1911  and  1912,  by  counties,  in  short  tons 

1911 


County 


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Christian    

Clinton   

Franklin    

Fulton     

Gallatin    

Grundy     

Henry     

Jackson     

Knox  

La   Salle    

Livingston    

Logan    

McDonough     

Macon     

Macoupin    

Madison     

Marion    

Marshall    

Menard    

Mercer    

Montgomery    

Peoria   

Perry    

Randolph     

Rock  Island 

St.    Clair   

Saline    

Sangamon     

Shelby    

Stark   

Tazewell    

Vermilion     

Will     

Williamson     

Other     counties" 
and   small  mint 


503,394 
061,568 
867,177 
425,108 
026,679 

50,227 
709,403 

52,118 
545,892 

1,251,017 
46,536 

259,014 
1,939 

118,084 
4,490,380 
2,954,710 

998,215 

384,679 

146,739 

267,845 
2,295,420 

924,951 
1,213,576 

739,287 

22,074 

3,634,322 

3,712,201 

4,733,096 

54,939 

8,460 

146,000 
3,159,386 

161,721 
6,137,410 

1,060,260 


66,226 

59,068 

98,891 

61,800 



11,465 

42,583 



28.922 

101,556 



59,325 

47,025 



11,443 

1,338 



28,505 

38,892 



35,962 

2,642 



86,410 

55,451 



28,832 

1,304 



286,668 

72,785 



39,380 

3,507 



49,896 

25,950 



6,056 

32 



110,334 

7,785 



67,382 

130,450 



118,381 

79,614 



187,324 

38,787 



20,301 

19,004 



36,126 

7,612 



17,417 

12,290 



37,622 

62,772 



86,641 

25,770 



17,103 

41,613 



23,124 

15,335 



39,848 

4,061 



187,960 

109,197 



36,614 

71,595 



255,767 

148,972 



21,902 

4,774 



27,033 

1,800 



67,274 

7,509 



172,018 

53,796 



10,824 

5,852 



195,013 

195,831 

85,775 

232,208 

64,967 

85,775 

2,806,197 

1,623,319 

1,628,688 

1,222,259 

921 ,225 

3,555,586 

2,133,029 

63,008 

776,800 

90,722 

687,753 

30,136 

1,610,470 

S9.423 

334,860 

8,027 

236,203 

4,688,212 

3,152,705 

1,224,326 

423,984 

190,477 

297,552 

2,395,814 

1,037,362 

1,272,292 

777,746 

65,983 

3,931,479 

3,820,410 

5,137,835 

81,615 

37,293 

220,783 

3,385,200 

178,397 

6,614,029 

1,357,435 


$2,569,897 

1,211,196 

896,667 

3,781,363 

2,706,871 

71,588 

1,254,323 

156,560 

906,645 

53,620 

2,676,710 

139,675 

388,724 

17,822 

369,591 

4,436,723 

3,094,573 

1,237,569 

705,130 

221,786 

421,922 

2,395,461 

1,285,259 

1,216,946 

755,451 

123,474 

3,566,857 

4,144,308 

5,248,253 

139,983 

63,007 

293,182 

3,694,799 

308,560 

6,888,812 

2,076,171 


$1.58 

219 

.99 

132 

.97 

160 

1.07 

206 

1.27 

174 

1.14 

167 

1.61 

220 

1.73 

193 

1.32 

147 

1.78 

186 

1.66 

223 

1.56 

149 

1.16 

124 

2.22 

189 

1.56 

200 

.95 

201 

.98 

154 

1.01 

184 

1.66 

218 

1.16 

194 

1.42 

168 

1.00 

191 

1.24 

208 

.96 

139 

.97 

160 

1.88 

166 

.91 

157 

1.08 

204 

1.02 

175 

1.72 

202 

1.69 

235 

1.33 

228 

1.09 

248 

1.73 

206 

1.04 

170 

1.53 

239 

$1.11 

188 

3,873 
2,158 
1,292 
4,064 
3,693 

138 
1,865 

183 

1,140 

83 

3,547 

341 

680 
37 

610 
4,638 
4,109 
1,664 
1,051 

343 

599 
2,740 
1,477 
2,122 
1,238 

106 
5,113 
4,895 
6,936 

197 
54 

336 
3,942 

411 
8,527  • 


76,600 


"Bond,   Calhoun,   Greene,  Hancock,  Jefferson,  Johnson,  McLean,   Morgan,  Moultrie,   Putnam, 
Schuyler,  Scott,  Warren,  Washington,  White,  and  Woodford  counties. 


MINERAL   RESOURCES   IN   1911   AND   1912  31 

Table  4. — Coal  production  of  Illinois  in  1911  and  1912,  by  counties,  in  short  tons 

— Concluded 
1912 


County 


c 
a 
& 


"  in  « 

fl   3   U 

o  rt  a 

**      g 

o  f  >, 


,_ 

o 

0) 

X 

«  u 

a* 

o 

*j  c 

e 

«  rt 

•" 

^g 

£3 

§ 

2E 


<  o 


Bureau     

Christian    

Clinton     

Franklin    

Fulton     

Gallatin    

Grundy     

Henry     

Jackson    

Knox  

La  Salle    

Livingston    

Logan     

McDonough     

Macon    

Macoupin    

Madison     

Marion     

Marshall    

Menard    

Mercer     

Montgomery    

Peoria     

Perry    

Randolph     

Rock    Island    

St.    Clair   

Saline     

Sangamon     

Shelby    

Stark     

Tazewell    

Vermilion     

Will     

Williamson     

Other    counties0 
and    small    mines. 


1,560,490 

1,250,722 

978,791 

4,282,721 

2,337,698 

48,977 

480,549 

17,000 

629,550 

1,156,290 
24,918 

392,374 
3,178 

148,443 
4,791,107 
3,804,878 
1,451,864 

361,335 

116,431 

364,886  ■ 
2,092,984 
1,097,830 
1,361,180 

752,609 

15,456 

4,437,137 

4,293,635 

5,260,048 

153,045 
10,881 

192,423 
3,179,572 

111,833 
6,982,822 

1,160,873 


48,706 

68,121 

152,163 

64,961 

12,947 

48,741 

39,878 

119,685 

54,323 

61,403 

14,399 

868 

30,690 

29,548 

39,863 

1,750 

29,806 

43,834 

21,417 

876 

307,696 

73,605 

39,219 

1,637 

56,638 

17,516 

10,954 

314 

136,047 

7,100 

80,155 

115,312 

124,515 

96,485 

48,313 

48,526 

66,443 

21,882 

53,797 

7,350 

15,635 

12,497 

43,122 

46,717 

101,958 

25,786 

31,128 

51,806 

30,924 

14,630 

47,477 

3,884 

182,573 

115,130 

34,699 

89,540 

298,353 

156,341 

24,210 

8,246 

21,845 

1,450 

71,224 

7,674 

201,243 

54,108 

14,063 

4,910 

69,188 

302,497 

238,250 

62,105 

793,861 

1,786,835 

1,677,317 
1,467,846 
1,040,479 
4,442,284 
2,453,424 
64,244 

540,787 
58,613 

703,190 

22,293 

1,537,591 

65,774 

466,528 
14,446 

291,590 
4,986,574 
4,025,878 
1,548,703 

449,660 

177,578 

393,018 
2,182,823 
1,225,574 
1,444,114 

798,163 

66,817 

4,734,840 

4,417,874 

5,714,742 

185,501 
34,176 

271,321 
3,434,923 

130,806 
7,354,507 

1,461,228 


59,885,226    $70,294 


$2,736,737 

1,687,823 

1,073,188 

5,389,076 

3,193,202 

72,295 

963,365 

104,602 

968,303 

39,765 

2,706,718 

130,847 

574,713 

31,820 

413,179 

4,894,191 

4,386,620 

1,666,346 

812,020 

240,850 

594,171 

2,348,084 

1,580,021 

1,518,746 

814,922 

107,377 

4,656,454 

4,924,839 

6,335,965 

252,865 

57,128 

348,063 

3,940,780 

242,805 

8,214,769 

2,271,689 


$1.63 

224 

1.15 

167 

1.03 

171 

1.21 

204 

1.30 

201 

1.13 

147 

1.78 

162 

1.78 

174 

1.38 

160 

1.78 

163 

1.76 

224 

1.99 

216 

1.23 

186 

2.20 

178 

1.42 

163 

.98 

206 

1.09 

184 

1.08 

212 

1.81 

240 

1.36 

169 

1.51 

209 

1.08 

192 

1.29 

213 

1.05 

146 

1.02 

138 

1.61 

180 

.98 

162 

1.11 

204 

1.11 

178 

1.36 

142 

1.67 

188 

1.28 

325 

1.15 

234 

1.86 

201 

1.12 

187 

1.56 

237 

$1.17 

194 

2,075 
1,336 
4,499 
3,578 

164 
1,595 

126 

1,068 

60 

3,275 

127 

678 
48 

581 
5,061 
4,466 
1,651 
1,065 

335 

479 
2,665 
1,721 
1,968 
1,116 

122 
5,799 
5,204 
7,030 

339 
43 

376 
4,149 

408 
8,602 

2,481 


"Bond,    Calhoun,    Edgar,    Greene,  Jefferson,    McLean,   Morgan,    Moultrie,    Putnam,    Schuyler, 
Scott,  Warren,  Washington,  White,  and   Woodford  counties. 


32 


BIENNIAL  REPORT 


COKE 

Most  of  the  coal  for  the  coking  establishments  in  Illinois  comes  from 
West  Virginia;  this  imported  material  is  used  with  Illinois  coal  in  a 
proportion  of  4  to  1,  a  mixture  that  makes  a  very  satisfactory  product. 
All  the  coke  produced  in  Illinois  in  1911  and  1912  was  made  in  retort 
ovens. 

In  1911  the  output  exceeded  that  of  the  previous  year,  but  as  the 
price  fell  from  $4.43  to  $3.97  the  value  of  the  total  State  production  was 
considerably  lower.  At  South  Chicago  200  Semet-Solvay  by-product 
ovens  operated,  and  at  Joliet  were  280  Koppers  regenerator  by-product 
ovens. 

In  1912  a  record  in  total  quantity  and  in  total  value  of  output  was 
made,  but  in  spite  of  this  the  rank  of  Illinois  amongst  other  states  fell 
to  fifth  due  to  the  enlargement  of  the  establishment  at  Gary,  Indiana, 
thus  advancing  that  State  from  fifth  to  third  rank.  The  By-Products 
Coal  Corporation  at  South  Chicago  built  40  new  ovens ;  the  North  Shore 
Gas  Company  at  Waukegan  began  operations  with  13  ovens;  and  the 
Coal  Products  Manufacturing  Company  at  Joliet  also  opened  up  business 
in  1912  with  35  ovens.  The  Illinois  Steel  Company  at  Joliet  made  no 
enlargements  during  this  year.  The  drop  in  average  yield  of  coal  in  coke 
is  due  probably  to  larger  proportion  of  Illinois  coal. 

Table  5  shows  the  statistics  for  the  manufacture  of  coke  in  Illinois 
for  the  past  4  years. 

Table  5. — Statistics  of  the  manufacture  of  coke  in  Illinois,  1909-1912 


Establish- 
ments 

Ovens 

Coal 
used 

Yield 
of  coal 
in  coke 

Coke 
produced 

Total  value 
of  coke 
at  ovens 

Value  of 
coke  at 

Built 

Building 

ovens   per 
ton 

1909 

1910 

1911 

1912 

5 
5 
6 
6 

468 
508 
506 
«594 

40 

0 

48 

MO 

Short 
tons 
1,682,122 
1,972,955 
2,087,870 
2,316,307 

Per  cent 

75.9 

76.8 
77.1 
76.2 

Short 
tons 
1,276,956 
1,514,504 
1,610,212 
1,764,944 

$5,361,510 
6,712,550 
6,390,251 
8,069,903 

$4.20 
4.43 
3.97 
4.57 

"Includes  253   Semet-Solvay,   1315   Koppers,   and  24   Belgian    ovens. 
&Semet-Solvay  ovens. 

PIG  IRON 

The  pig  iron  of  Illinois  is  made  from  ore  shipped  by  lake  to  the 
Chicago  smelters  from  the  northern  iron-ore  districts.  For  this  reason 
the  value  of  this  product  is  not  included  in  the  total  value  of  mineral 
production  for  Illinois.  In  both  1911  and  1912  a  rank  of  third  among 
the  states  was  maintained,  having  been  preceded  by  Pennsylvania  and 
Ohio. 


MINERAL   RESOURCES   IN   1911   AND   1912 


33 


In  1911  a  marked  decline  in  output  of  pig  iron  prevailed  in  all  the 
states  producing  this  material.  Illinois  suffered  a  drop  of  21.9  per  cent 
as  compared  with  1910;  but  in  1912  an  increase  prevailed  throughout  the 
country,  and  Illinois  put  out  37.8  per  cent  more  than  the  preceding  year. 


Table  6.- 

— Statistics 

of  pig  iron 

marketed  in 

Illinois,  1910-1912 

Year 

Quantity 

Value 

Average 
price  per 

ton 

Percentage 

of  U.  S.  total 

quantity 

1910    

Long  tons 
2,606,335 
2,036,081 
2,806,378 

$41,465,543 
31,152,927 
42,828,816 

$15.91 
15.30 
15.26 

9.02 

1911    

8.71 

1912     

9.29 

PETROLEUM 

The  main  oil  field  of  Illinois  is  a  feature  of  the  La  Salle  anticline 
that  extends  from  La  Salle  south  and  east  through  St.  Francisville  and 
into  Indiana.  The  oil-bearing  sands  are  in  the  Pennsylvanian  and  Miss- 
issippian  series,  the  richest  of  these  being  known  as  the  Kirkwood  and 
McClosky  sands,  both  of  Mississippian  age.  Oil  and  gas  was  discovered 
near  Casey  in  1865,  but  development  of  the  field  did  not  begin  till  1904. 
As  shown  by  Table  7,  the  production  of  petroleum  in  Illinois  increased 
phenomenally  till  a  maximum  was  reached  in  1908.  In  1909  a  decline 
was  suffered,  but  the  following  year  active  drilling  in  Lawrence  County 
revealed  new  possibilities  in  two  previously  unknown  sands,  the  Tracey 
and  McClosky ;  also  the  Centralia-Sandoval  field  was  developed  follow- 
ing recommendations  by  the  State  Geological  Survey. 

In  1911  the  rank  of  third  amongst  oil-producing  states  was  main- 
tained, but  a  drop  in  total  output  of  5.5  per  cent  resulted  from  the  lack 
of  new  prolific  fields.  The  Carlyle  area  was  developed  as  a  result  of 
Survey  investigations,  and  about  120  wells  yielded  approximately  4,500 
barrels  daily ;  this  field  is  very  limited  and  probably  will  not  last  long. 
Oil  and  considerable  gas  were  found  near  Carlinville  late  in  1911,  but 
the  production  did  not  affect  the  statistics  for  that  year. 

Further  decline  in  total  production  (S.7  per  cent)  in  Illinois  was  felt 
in  1912,  as  no  great  extensions  of  the  producing  fields  were  developed. 
The  marked  increase  in  prices,  however,  made  the  total  value  greater 
than  the  previous  year.  The  chief  interest  lay  in  northern  Wabash 
County  where  a  200-barrel  well  caused  considerable  prospecting,  and 
only  13  of  the  40  borings  yielded  over  100  barrels  daily ;  20  were  dry. 

Table  7  shows  the  production  and  value  of  oil  in  Illinois  from  1889 
to  1912. 


34 


BIENNIAL  REPORT 


Table  7. — Marketed  production  in  barrels  and  value  of  petroleum  in  Illinois, 

1889-1912 


Year 

Marketed 
production 

Percentage 
of  U.  S. 

Value 

Yearly 
average  price 

production 

per  barrel 

1889-1904 

6,576 

1905 

181,084 

0.14 

$    116,561 

$0,644 

1906 

4,397,050 

3.47 

3,274,818 

0.745    . 

1907 

24,281,973 

14.62 

16,432,947 

0.677 

1908 

33,686,238 

18.76 

22,649,561 

0.672 

1909 

30,898,339 

16.87 

19,788,864 

0.640 

1910 

33,143,362 

15.82 

19,669,383 

0.593 

1911 

31,317,038 

14.21 

19,734,339 

0.630 

1912 

28,601,308 

12.88 

24,332,605 

0.851 

In  the  following  table  are  the  dates  of  changes  and  changes  in  prices 
at  wells  of  different  grades  of  petroleum  from  1910  to  1912. 


Table  8. — Fluctuation  in  prices  of  Illinois  petroleum  per  barrel,  1910-1912 


Date 


Below 
30°  B. 


Above 
30°  B. 


Date 


Below 
30°  B. 


Above 
30°  B. 


1910 
Jan.    1.. 

1911 
Jan.  1.. 
May  2.  . 
June  14. 
Sept.  15 
Sept.    19 

1912 
Jan.  1.. 
Jan.  2.. 
Jan.  3.. 
Jan.  24. 
Feb.  1.. 
Mar.  4. 
Apr.    24. 


$0.60 

.60 
.63 
.65 
.67 
.67 

.67 
.70 
.72 
.75 
.78 
.81 
.83 


$0.52 

.52 
.55 
.55 
.55 

.57 

.57 
.60 
.62 
.65 
.68 
.71 
.73 


1912 — con. 

May   24 

June    13  .  .  . 

June  27 

July    25 

Sept.    12  .  .  . 

Oct.    28 

Nov.    9 

Nov.    15  ..., 

Nov.  25 

Dec.   2 

Dec.   9 

Dec.    16 

Dec.   20 

Dec.   23 


$0.85 


.87 

.90 
.92 
.94 
.96 
.99 
1.02 
1.05 

1.08 


$0.75 

.77 

.79 

.82 

.84 

.87 

.89 

.91 

.93 

.96 

.99 

1.02 

1.05 

1.08 


By  far  the  large  proportion  of  drilling  for  the  past  three  years  has 
been  in  Lawrence  and  Crawford  counties.  Table  9  presents  by  counties 
the  number  of  wells  drilled,  the  total  initial  and  average  initial  daily 
output  of  new  wells  from  1910  to  1912  inclusive. 


MINERAL   RESOURCES   IN    1911   AND    1912 


35 


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36 


BIENNIAL  REPORT 


NATURAL  GAS 

Natural  gas  is  a  minor  by-product  in  the  oil  industry.  This  product 
is  more  widespread  in  Illinois  than  the  oil,  but  the  available  quantity 
small.  Some  small  towns  or  establishments  are  supplied  with  it,  but 
the  total  production  is  slight.  The  areas  that  are  producing  commercially 
in  this  State  are  in  Bond,  Clark,  Crawford,  Lawrence,  Cumberland, 
McLean,  and  Macoupin  counties.  The  larger  proportion  of  gas  consumed 
is  utilized  for  power  purposes  and  mostly  for  drilling  and  operating  in 
the  oil  fields,  and  as  this  gas  is  not  measured,  only  approximate  figures 
for  natural  gas  can  be  given.  In  Bureau,  Champaign,  Dewitt,  Edgar, 
Lee,  Pike,  Logan,  Morgan,  and  Mclienry  counties  are  numerous  shallow 
or  drift  wells  that  supply  only  sufficient  gas  for  one  family.    The  gas  orig- 


Table 

10. — Record   of  nai 

ural  gas 

industry 

in  Illinois,  1910-1912 

Gas  produced 

Gas  consumed 

Wells 

Year 

Number 
of  pro- 
ducers 

Value 

Number  of  consumers 

Value 

Drilled 

Produc- 

Domestic    Industrial 

Gas    |    Dry 

tive 
Dec.   31 

1910    

1911    

1912    

207 
225 
223 

$613,642 
687,726 
616,467 

"10,109 
"10,078 
"10,691 

"261 
"293 
"212 

"$613,642 
"687,726 
"616,467 

64 
69 
56 

31 

78 
147 

458 
458 
447 

"Includes  number   of  consumers   and  value   of   gas   consumed   in   Vincennes,   Ind. 


Table  11. — Depth  and  gas  pressure  of  wells  in  Illinois 

,  by  counties 

,  1910-1912 

Depth 

Pressure 

County 

1910 

1911 

1912 

Bond     

Lawrence     . 

Bureau 

Champaign 

Clark     

Crawford    .  . 
Cumberland 
Dewitt 
Edgar 

Lee      

Logan 
McHenry     . 
McLean 
Macoupin     . 
Morgan     .  . . 
Pike    


Feet 
900—1,900 


Pounds 
200—750 


98— 

357 

0—  23 

80— 

140 

15—  32 

250— 

610 

35—  45 

500— 

,550 

20—225 

500— 

575 

94— 

127 

25—  50 

260— 

600 

75—127 

126— 

280 

IS—  28 

84— 

90 

160— 

372 

260— 

400 

96— 

350 

4—  10 

Pounds 

100—350 

0—  42 
15—  30 
10—  60 
10—150 


20— 

50 

so— 

90 

19— 

28 

10—  22 


0—100 
1—  20 


Pounds 

40—410 

0—  80 

0—  20 

15—105 

20—200 

0—  50 
75—130 
12—  28 


0—100 
0—  10 


inates  from  the  decay  of  vegetal  matter  in  the  glacial  drift,  possibly  some 
soil  horizon  between  drift  deposits  of  two  different  ages. 

In  1911   there  was  an  increase  in  production  of  natural  gas.     The 


MINERAL   RESOURCES   IN   1911   AND   1912  37 

average  price  also  advanced  from  21.9  cents  to  23.05  cents  for  domestic 
consumption  and  from  6.1  cents  to  7.25  cents  for  industrial  consumption. 
No  important  new  fields  were  opened  in  1911.  A  total  of  78  dry  holes 
and  69  gas  producers  were  drilled  during  the  year. 

As  compared  with  1911  the  figures  for  1912  show  a  reduction  in  the 
total  output  and  value — 5,603,368,000  cubic  feet  valued  at  $616,467,  the 
average  price  being  11  cents  per  thousand.  During  this  year  a  few 
plants  for  gasoline  extraction  were  installed  and  operated  successfully. 

Tables  10  and  11  present  the  record  of  the  natural  gas  industry 
from  1910  to  1912. 

GASOLINE 

Although  gasoline  has  been  produced  from  natural  gas  in  Pennsyl- 
vania for  some  12  or  15  years,  it  has  not  been  till  recently  that  steps 
have  been  taken  to  develop  this  as  a  special  industry.  For  about  40 
years  pumps  in  the  vicinity  of  Tidioute,  Pennsylvania,  have  been  produc- 
ing this  material,  but  it  was  not  saved  till  about  12  years  ago ;  since  then 
this  county  has  been  manufacturing  it  successfully.  This  promises  to 
become  a  very  flourishing  business  as  large  quantities  of  gas  are  now 
being  wasted  that  might  be  utilized  thus. 

Not  all  natural  gas  is  capable  of  yielding  gasoline.  Gas  may  be 
classified  as  "wet"  and  "dry" ;  a  chemical  analysis  will  show  to  which 
class  a  gas  belongs  and  its  degree  of  saturation  with  gasoline.  A  produc- 
tion of  8  to  10  gallons  per  thousand  cubic  feet  of  gas  is  reported  as  a 
maximum,  but  probably  2  gallons  is  a  fair  average.  The  two  methods 
of  extraction  are  the  cooling  process  without  compression  and  the  com- 
pression under  high  pressure.  The  degree  of  saturation  of  the  gas  with 
gasoline  governs  the  methods  adopted.  The  subject  has  been  described 
fully  in  Technical  Paper  No.  10  of  the  U.  S.  Bureau  of  Mines. 

In  1911  the  low  prices  of  gasoline  hindered  the  profitable  develop- 
ment of  the  industry.  In  Illinois  three  companies  reported  activity,  the 
Kewanee  Oil  &  Gas  Company  and  the  Mahutska  Oil  Company,  both  in 
Crawford  County  and  the  Shaffer-Smathers  Oil  Company  in  Lawrence 
County.  The  average  yield  of  gasoline  per  thousand  cubic  feet  ranged 
from  \l/2  to  3  gallons.  The  gas  used  in  Illinois  was  from  the  deep-sand 
low-pressure  fields  of  the  southeastern  portion  of  the  State. 

In  1912  the  conditions  were  more  favorable  for  progress  as  the 
prices  advanced  considerably.  Illinois  stood  sixth  in  point  of  output 
of  natural-gas  gasoline  in  1912,  with  a  marked  increase  of  about  350 
per  cent  over  the  production  of  1911.  A  new  plant  in  Crawford  County 
opened  up  during  this  last  year,  and  the  yield  of  gasoline  per  thousand 
cubic  feet  of  gas  varied  from  \l/2  to  5  gallons. 


38 


BIENNIAL  REPORT 


CLAY-WORKING  INDUSTRIES 

Clay 

The  largest  portion  of  the  total  raw  clay  output  of  Illinois  is  fire 
clay ;  stoneware  clay  comprises  a  large  fraction ;  and  brick  clay,  modelling 
clay,  and  clay  for  medicinal  uses  comprise  but  small  parts  of  the  total 
quantity.  In  both  1911  and  1912  Illinois  stood  6th  among  clay-producing 
states  in  total  value  of  clay  mined. 

Table  12. — Production  in   short   tons  and  value   of  clay  mined   and  marketed  in 

Illinois,  1910-1912 


Fire  clay 

Stoneware  clay 

Brick  clay 

Miscellaneous 

Total 

Year 

Quan- 
tity 

Value 

Ouan- 
tity 

Value 

Quan- 
tity 

Value 

Ouan- 
tity 

Value 

Quan- 
tity 

Value 

1910    

1911    

1912    

82,878 
71,479 
92,963 

$111,078 

91,623 

110,204 

42,410 
30,402 
29,761 

$34,202 
29,473 
22,605 

13,704 
16,800 
21,684 

$16,344 
25,200 
32,526 

49,811 
64,155 
32,150 

$29,272 
37,530 
27,328 

188,803 
182,836 
176,558 

to  oo  to 

Nl    CO    O 

Oi    OO    OO 
O)    M   to 

Clay  Products 

In  1911  and  1912  Illinois  held  third  rank  in  value  of  brick  and  tile 
products ;  in  total  value  of  clay  products  a  status  of  fourth  was  main- 
tained. The  fluctuations  in  the  yearly  output  of  the  various  kinds  of 
wares,  as  shown  in  Table  13,  were  in  harmony  with  the  total  figures  for 
the  country. 

In  1911  Illinois  stood  first  in  the  values  of  common  brick  and  archi- 
tectural terra  cotta,  second  in  quantity  of  common  brick  and  in  value 
and  quantity  of  vitrified  brick,  third  in  the  values  of  draintile  and  fire- 
proofing,  and  sixth  in  value  of  sewerpipe.  Of  the  total  quantity  of 
common  brick  manufactured  in  Illinois  682,720,000  brick,  or  63.54  per 
cent,  was  from  Cook  County. 

In  1912  this  State  held  first  rank  in  value  of  architectural  terra 
cotta,  second  in  value  and  in  number  of  common  brick  and  in  value  and 
number  of  vitrified  paving  brick,  fourth  in  value  of  draintile,  and  fifth 
in  values  of  sewerpipe  and  fireproofing.  Cook  County  manufactured 
765,845,000  common  brick  or  63.27  per  cent  of  the  State's  total  output. 


MINERAL  RESOURCES   IN   1911   AND   1912 


39 


Table  13.— Clay  products  in  Illinois  1910-1912 


Product 


Brick  : 

Common — 

Quantity    

Value    

Average  per   M 

Vitrified— 

Quantity    

Value    

Average  per   M 

Front- 
Quantity    

Value    

Average  per   M 

Fancy   or   ornamental value. 

Enameled   value . 

Fire    value . 

Stove     lining value. 

Draintile     value. 

Sewer    pipe value. 

Architectural  terra  cotta value. 

Fireproofing .  .value. 

Tile,  not  drain value . 

Pottery  : 

Red    earthenware value. 

Stoneware    and    yellow    and    Rockingham    ware 

value . 

White   ware   including   C.    C.    ware,   white   gran- 
ite,     semiporcelain     ware,     and     semivitreous 

porcelain    ware value. 

Sanitary  ware value. 

Porcelain  electrical  supplies value. 

Miscellaneous    value. 

Total    value 


1910 


Number   of  active   firms   reporting 

Rank   of   State 

Percentage  of  total  U.  S.  value. 


1,196,526,000 

$6,896,836 

$5.76 

115,903,000 

$1,415,355 
$12.21 

22,138,000 

$274,699 

$12.41 

$10,875 

(a) 

$368,730 


$1,613,698 
$538,633 

$1,680,438 
$552,905 


$25,658 
$708,95S 


$1,039,376 


$15,176,161 


346 

4 

10.51 


1911 


1,074,486,000 

$6,126,911 

$5.70 

124,623,000 

$1,627,683 

$13.06 

19,786,000 

$240,135 

$12.14 

$10,281 

(«) 

$286,039 


1912 


1,210,499,000 
$6,437,331 

$5.32 

136,708,000 

$1,839,721 

$13.46 

21,894,000 

$268,433 

$12.26 

$8,785 

(a) 

$319,619 


$1,372,049 
$507,694 

$1,879,275 
$552,994 
(a) 

$41,875 
$832,813 


(a) 

(a) 
(a) 

$855,262 

$14,333,011 


330 

4 

10.46 


$1,189,910 
$500,844 

$2,485,012 
$507,222 


$35,827 
$675,244 


(a) 

(a) 
(a) 
$943,042 

$15,210,990 

301 

4 

10.48 


"Included  in  "Miscellaneous." 

STONE 
Sandstone 
Most  of  the  sandstone  quarried  in  Illinois  was  used  for  road-making. 
In  1911  the  value  of  production  was  $30,953;  in  1912,  $32,720.  A  few 
of  the  quarries  are  in  the  Ordovician  beds  of  the  northern  part  of  the 
State,  but  the  majority  are  along  the  border  of  the  area  of  "Coal  Meas- 
ures" in  the  western  and  southern  parts  of  the  State. 


Limestone 

In  value  of  limestone  quarried  in  1911  and  1912,  Illinois  held  fourth 
rank,   having   been   preceded   by   Pennsylvania,    Indiana,   and    Ohio.      A 


40 


BIENNIAL  REPORT 


position  of  second  in  value  of  crushed  stone  was  held  by  Illinois  in  both 
years,  the  first  place  having  belonged  to  Ohio.  Table  14  shows  the 
production  in  Illinois  from  1910  to  1912. 

In  Illinois  the  Ordovician  formations  of  the  north-central  part,  the 
Silurian  of  the  Chicago  area,  and  the  Silurian  and  Devonian  of  the 
northwestern  part  of  the  State  are  worked  for  limestone.  Along  the 
Mississippi  and  lower  Illinois  valley  practically  all  the  quarries  are  in 
Mississippian  rocks  well  exposed  in  the  bluffs.  On  the  Ohio  of  southern 
Illinois  the  Mississippian  rocks  are  also  quarried.  In  eastern  Illinois  the 
McLeansboro  limestone  of  the  Pennsylvanian  series  is  a  notable  fluxing 
stone  used  in  the  Chicago  industries. 

Most  of  the  Ordovician  limestones  are  magnesian,  though  some  high- 
calcium  beds  are  known ;  the  Silurian  limestones  are  also  magnesian, 
but  the  Devonian  are  high  in  calcium  carbonate.  The  Carboniferous 
rocks  are  mostly  high  in  calcium  and  low  in  magnesium,  but  the  Miss- 
issippian beds  are  likely  to  contain  a  considerable  percentage  of  silica 
commonly  in  the  form  of  chert. 

Table  14.— Value  of  production  of  limestone  in  Illinois  according  to  uses,  1910-1912 

Uses 


Rough    building     .  .  . 

Dressed   building    .  . 

Paving     

Curbing     

Flagging      

Rubble    

Riprap     

Crushed   stone — 
Road-making 
Railroad   ballast 
Concrete      

Flux     

Miscellaneous    

Total    


1910 

1911 

1912 

$50,958 

$34,252 

$15,413 

9,963 

16,775 

19,293 

128,413 

81,935 

53,169 

1,050 

5,071 

33,063 

825 

2,979 

356 

236,315 

191,848 

187,478 

48,315 

28,275 

58,545 

954,409 

750,583 

1,054,676 

520,132 

453,465 

368,349 

953,502 

1,038,882 

963,617 

854,615 

728,544 

951,733 

89,218 

104,368 

103,092 

3,847,715 

3,436,977 

3,808,784 

LIME 

In  1911  and  1912  Illinois  stood  twelfth  in  quantity  of  lime  burned 
and  eleventh  in  value.    Table  15  gives  the  figures  for  the  last  three  years. 

Table  15. — Lime  burned  in  Illinois,  1910-1912 


Year 

Number 

of 

plants 

Quantity 

Value 

Average 

price 
per  ton 

1910 

14 
16 
15 

113,239 
92,169 
98,450 

$503,581 
423,762 
394,892 

$4.45 

1911         

4.60 

1912     

4.01 

MINERAL   RESOURCES    IN    1911    AND    1912 


41 


CEMENT 

In  1911  Illinois  ranked  fifth  in  both  value  and  quantity  of  Portland 
cement  produced ;  in  1912  we  held  fifth  rank  in  quantity  and  sixth  in  value. 

The  "Lower  Magnesian"  limestone  furnished  material  for  natural 
cement  at  Utica,  La  Salle  County.  This  plant  was  one  of  15  natural 
cement  plants  in  operation  in  the  United  States. 

Table   16. — Portland  cement  industry   in   Illinois,  1910-1912 

(Figures    opposite    P    relate    to    production;    those    opposite    S    to    shipments.) 


Year 

Number 

of 
plants 

Quantity 

Value 

Average 

price 

per  barrel 

1910    P 

1911    P 

i 

4,459,450 
4,582,341 
4,299,357 
4,602,617 

$4,119,012 

3,583,301 
3,212,818 
3,444,085 

$0.90 
.79 

1912     1    7, 

\     S 

.75 

SAND  AND  GRAVEL 

In  quantity  of  sand  and  gravel  produced  Illinois  ranked  first  in  1911 
and  second  in  1912 ;  in  value  of  this  production  this  State  stood  fourth 
both  years. 

Most  of  the  sand  and  gravel  pits  in  Illinois  are  in  river  deposits. 
Some  are  located  in  pockets  in  the  drift.  The  glass  sand  is  the  St.  Peter 
sandstone  that  outcrops  in  the  vicinity  of  Oregon,  Ottawa,  and  La  Salle. 

Table  17. — Production  in  short  tons  and  values  of  different  kinds  of  sand  and  gravel 

in  Illinois,  1910-1912 


Kind  of  sand 


1910 


1911 


1912 


Quantity         Value       Quantity         Value      Quantity  ;      Value 


Glass   sand 

Molding   sand 

Building    sand    

Grinding   and   polishing   sand 

Fire   and    furnace    sand 

Engine   sand 

Paving    sand     

Other    sands 

Gravel     


268,654 

407,232 

1,756,652 


$216,531 
215,742 
473,209 


97,633 
43,147 


60,932 
6,840 


1,211,564        130,756 


251,907 

237,359 

1,875,814 

59,880 

62,107 

46,89-7 

318,671 

1,862,000 


$171,978 

120,690 

691,846 

41,765 

25,643 

6,158 

125,624 

164,292 


323,467 

540,728 

1,910,911 

67,040 

<n) 

59,151 

30,581 

499,685 


Total     8,586,508     1,730,795     8,488,683     1,990,922     6,957,901     1,929,822 


$225,434 

268,521 

598,884 

49,196 

(«) 

12,916 
13,958 
75,391 


4,801,626        626,785     3,774,048        642,926     3,481,638  \      664,552 


(0)Concealed  in  total. 


FLUORSPAR 


A  noteworthy  feature  in  the  fluorspar  industry  of  this  country  is 
the  continuous  decrease  in  the  importation  of  foreign  spar  and  the  in- 
crease in  the  quantity  of  domestic  spar  demanded  by  the  steel  markets. 


42 


BIENNIAL  REPORT 


For  many  years  Illinois  has  been  the  principal  fluorspar-producing 
State,  about  90  per  cent  of  the  total  for  the  United  States  coming  from 
Pope  and  Hardin  counties  where  large  tabular  bodies  of  almost  pure 
material  are  found.  The  output  for  1912  would  no  doubt  have  been 
much  greater  had  not  the  mines  at  Fairview  and  Rosiclare  been  flooded 
by  Ohio  River  in  the  spring.  Other  producing  states  are  Colorado,  Ken- 
tucky, New  Hampshire,  and  New  Mexico. 

Table  18. — Production  in  short  tons  and  value,  of  fluorspar  in  Illinois,  1910-1912 


Year 

Quantity 

Value 

1910         

47,302 

68,817 

114,410 

$277  764 

1911     

481,635 

1912     

756,653 

MINERAL  WATERS 

Practically  all  the  Illinois  water  is  used  for  the  table.  In  1911  there 
were  resorts  at  four  of  the  springs,  and  the  water  of  five  was  used  for 
bathing;  in  1912  there  were  resorts  at  two  of  the  springs,  and  the  water 
of  three  was  used  for  bathing.  Besides  the  quantity  reported  as  sold, 
considerable  was  used  in  the  manufacturing  of  soft  drinks. 


Table  19. — Production  in  gallons  and  value  of  mineral  water  in 

Illinois,  1910-1912 

Year 

Number  of 
springs 

Quantity 

Value 

Average  price 
per  gallon 

1910     

16 
14 
17 

1,117,620 
1,304,950 
1,143,625 

$83,148 
82,330 
74,445 

$0.07 

1911     

.06 

1912    

.07 

SILICA 

Tripoli  is  a  light,  porous,  siliceous  rock  having  resulted  from  the 
decomposition  of  a  chert  or  a  siliceous  limestone.  In  Alexander  and 
Union  counties  the  heavy  bed  of  Devonian  chert  is  highly  decomposed 
in  places,  and  the  resultant  material  is  a  fine  white  powder  that  is  mined 
at  several  localities. 

The  Illinois  product  is  sized  by  screening  and  floating;  it  is  used 
as  a  wood-filler,  wood  polisher,  adulterant  in  paints,  and  for  other 
purposes. 

Table  20. — Value  of  tripoli  mined  in  Illinois,  1910-1912 

1910   $33,390 

1911   45,910 

1912   27,339 


MINERAL  RESOURCES   IN   1911   AND   1912 


4  3 


PYRITE  AND  SULPHURIC  ACID 

In  both  1911  and  1912  Illinois  held  fourth  place  in  production  of 
pyrite,  which  is  obtained  as  a  by-product  in  coal  mining.  Most  of  it 
comes  from  Vermilion  County,  where  it  occurs  in  lenses  that  can  easily 
be  thrown  out  in  loading  the  coal.  Throughout  most  of  Illinois  this 
pyrite  is  finely  disseminated  in  the  coal  and  can  not  be  separated. 

The  sulphuric  acid  statistics  were  collected  for  the  first  time  in 
1911,  when  Illinois  produced  114,805  short  tons  (60°  Baume),  valued 
at  $958,591;  in  1912  the  output  was  160,378  short  tons,  valued  at 
$1,064,564.  In  this  State  sulphuric  acid  is  a  by-product  in  the  smelting 
of  zinc  in  which  process  the  waste  gases,  sulphur  dioxide  and  sulphur 
trioxide  are  converted  into  the  acid. 


Table  21. 

— Production  in 

long  tons  and  value  of  pyrite  mined  in  Illinois,  1910-1912 

Year 

Quantity 

Value 

Average  price 
per  ton 

1910    

8,541 
17,441 
27,008 

$28,159 
47,020 
62,980 

$3.30 

1911     

2.70 

1912    

2.33 

LEAD,  ZINC,  AND  SILVER 

The  lead  and  zinc  deposits  of  Illinois  fall  into  two  widely  separated 
regions  of  greatly  different  geologic  character.  Those  of  the  northwest 
corner  of  the  State  belong  to  the  Upper  Mississippi  Valley  region ;  those 
of  southern  Illinois  (Pope  and  Hardin  counties)  to  the  Illinois-Kentucky 
fluorspar  district. 

Northern  Illinois. — The  ores  of  Jo  Daviess  County  occur  dissem- 
inated throughout  the  Galena  dolomite  and  Platteville  limestone  or  in 
openings  known  as  "crevices",  "pitches",  or  "flats".  Galena  and  sphal- 
erite are  the  leading  ores,  and  associated  with  these  are  pyrite,  smith- 
sonite,  cerusite,  calcite,  dolomite,  and  other  minerals. 

The  two  producing  districts  of  this  area  are  the  Galena  district  and 
the  Elizabeth  district,  the  former  having  been  far  the  more  active  during 
1911  and  1912. 

Southern  Illinois. — The  lead  and  zinc  of  Pope  and  Hardin  counties 
is  associated  with  the  fluorspar  bodies  associated  with  jointing  and  fault- 
ing of  the  lower  Carboniferous  rocks.  The  mines  have  extended  to 
depths  of  300  and  500  feet  without  any  decrease  in  the  size  or  quality  of 
ore  bodies.  Both  galena  and  sphalerite  occur,  but  only  the  lead  is  in 
quantities  of  economic  value,  and  this  is  mined  only  incidentally  in  the 
concentration  of  the  spar. 


44 


BIENNIAL  REPORT 


The  galena  of  this  district  is  notably  argentiferous,  the  silver  content 
ranging  up  to  12  and  14  ounces  per  ton  of  lead  concentrates,  but  averaging 
from  4  to  6  ounces  per  ton  of  lead  concentrates. 

Table  22. — Tenor  of  lead  and  zinc  ore  and  concentrates  produced  in  Illinois, 

1911  and  1912 


1911 

1912 

Northern  Illinois 

153,313 

147,859 

Total  concentrates  in  crude  ore — 

cent. . 
cent. . 

0.6 
7.2 

0.6 

Zinc    

.  .per 

9.1 

Metal  content  of  crude  ore — 

Lead     

.  .per 

cent.  . 

0.4 

0.4 

Zinc      

.  .per 

cent. . 

3.2 

3.2 

Average  lead  content  of  galena  concentrates... 

.  .per 

cent. . 

79.4 

79.5 

Average  zinc  content  of  sphalerite  concentrates 

.  .  per 

cent. . 

45.3 

35.4 

Average  value  per  ton — 

$52.37 
$29.13 

$55.38 
$27.30 

Southern   Illinois 

70.0 

74.6 

$44.00 

$46.49 

Table  23. — Production  and  value  of  lead,  zinc,  and  silver  in  Illinois,  1910-1912. 

Lead 

Zinc 

Silver 

Year  and  district 

Quantity- 

Value 

Quantity- 

Value 

Quantity 

Value 

1910 


1912 


Northern   Illinois 
Southern    Illinois. 


Total 


{Northern    Illinois. 
Southern    Illinois. 
Total      


Northern    Illinois 
.Southern    Illinois. 


Total 


Short 

tons 

101 

272 

.  373 

625 
339 

964 

687 
595 

1,282 


23,936 

32,824 

56,250 
30,510 

86,760 

61,830 
53,550 

115,380 


Short 
tons 
3,549 


4,219 


4,065 


$383,292 


480,966 


560,970 


Fine 
ounces 

2,022 


3,036 


4,731 


$1,092 


1,609 


2,909 


MINERAL  PAINTS 

Both  basic  lead  sulphate  and  "blue  fume"  (sublimed  white  lead  and 
sublimed  blue  lead)  were  manufactured  directly  from  the  ores. 


OIL  AND  GAS  IN   COLCHESTER  AND  MACOMB 

QUADRANGLES 

By  Henry  Hinds 

(U.  S.  Geological  Survey  in  cooperation  -with  State  Geological  Survey) 


OUTLINE 

PAGE 

Location   of   quadrangles 45 

Stratigraphy    45 

Surface  deposits    45 

Pennsylvanian  series   46 

Carbondale  formation  46 

Pottsville   formation    46 

Mississippian  series    47 

Structure   48 

Oil  and  gas 48 

Gas  in  surface  deposits 48 

Deep  drilling  for  oil  and  gas 49 


II.     Geological  map  of  Colchester  and  Macomb  quadrangles 50 

PLATE 


LOCATION  OF  QUADRANGLES 

The  Colchester  and  Macomb  quadrangles  lie  in  west-central  Illinois 
between  latitudes  90°  31'  W.  and  91°  W.  and  longitudes  40°  15'  N.  and 
40°  30'  N.,  embracing  an  area  of  approximately  455  square  miles.  In 
this  territory  are  included  nearly  all  of  southern  McDonough  County,  a 
strip  5  miles  wide  on  the  east  edge  of  Hancock  County,  and  a  strip  2 
miles  wide  on  the  north  edge  of  Schuyler  County  as  shown  on  Plate  II. 
This  region  was  surveyed  topographically  in  1911  and  1912,  and  geolog- 
ically in  1912. 

STRATIGRAPHY 

Surface  Deposits 

The  thick  cover  of  loose  surface  materials  conceals  in  many  parts  of 
the  region  the  regularly  bedded,  indurated  rocks  beneath  them.  Scat- 
tered outcrops  of  the  older  beds  are  fairly  numerous,  for  example,  in  most 


(45) 


46  BIENNIAL   REPORT 

of  the  deeper  valleys  in  all  parts  of  the  Colchester  quadrangle,  except 
near  Troublesome  and  Spring  creeks.  The  older  rocks  have  been  reached 
by  the  deep  wells  near  Birmingham.  These  deep  drillings  confirm  the 
well-established  geological  principle  that  there  are  no  commercial  coal 
beds  in  strata  lying  below  the  Pennsylvanian  series. 

Pennsylvanian  Series   ("Coal  Measures") 

carbondale  formation 

The  Carbondale  formation  includes  the  strata  from  the  highest  indu- 
rated rocks  of  the  region  to  the  base  of  the  Murphysboro  (No.  2)  coal. 
At  Colchester  there  is  a  maximum  of  about  4  feet  of  this  formation,  the 
lower  part  being  a  blue  drab  shale  that  is  argillaceous  at  the  base  and 
more  sandy  at  the  top,  and  the  upper  part  a  thin-bedded  to  massive, 
brownish  sandstone  with  shale  partings.  The  distance  from  the  coal  to 
the  sandstone  varies  from  40  feet  in  a  few  places  near  Colchester  to  one 
foot  or  less  in  the  southern  part  of  the  Macomb  quadrangle.  In  the 
south-central  part  of  the  Macomb  quadrangle  the  maximum  thickness  of 
the  Carbondale  for  this  region  is  exposed.  There  are  here  as  much  as 
90  feet  of  sandy  and  argillaceous  shale  and  sandstone.  In  many  places 
there  is  massive  sandstone  on  or  near  the  Murphysboro  coal,  with  alter- 
nating shale  and  sandstone  beds  above  it.  No  trace  was  found  of  coal 
"No.  3,"  reported  by  Worthen  to  lie  30  to  50  feet  above  the  Murphysboro 
(No.  2)  coal  bed  in  Schuyler  and  Fulton  counties,  and  the  only  repre- 
sentatives of  its  limestone  cap  rock  are  small,  thin,  calcareous  lenses  in 
only  three  outcrops. 

POTTSVILLE    FORMATION 

The  strata  from  the  base  of  the  coal  bed  (Murphysboro  or  No.  2) 
mined  at  Colchester  and  elsewhere,  down  to  the  top  of  the  Mississippian 
limestones  are  included  in  the  Pottsville  formation.  The  first  and  lowest 
deposit  laid  down  was  a  coarse-grained  sandstone  composed  of  almost 
pure  translucent  quartz  grains"  in  a  slightly  ferruginous  cement,  and 
known  locally  as  a  "glass  sand."  Since  the  bed  occupies  the  depressions 
in  the  old  Mississippian  land  surface,  its  thickness  is  variable.  It  is  the 
only  Pennsylvanian  bed  exposed  in  most  of  the  west  half  and  southeast 
quarter  of  the  Colchester  quadrangle.  Pottsville  strata  are  somewhat 
variable  in  character,  though  sufficiently  persistent  to  be  recognized  and 
differentiated  by  careful  study  in  any  part  of  the  field.  The  following 
section  measured  near  Colchester  is  typical : 


OIL  AND  GAS  IN  COLCHESTER  AND   MACOMB  QUADRANGLES  47 

Typical  section  of  the  Pottsville  formation 

Distance 
below 
Description  of  strata  Thickness        coal  No.  2 

Feet  Feet 

Pottsville  formation — 

Clay,  drab  to  white 4  4 

Shale,  including  layers  of  red  sandstone  in  places 8  12 

Limestone,  dark  blue  to  bluish  gray,  nodular;  weathers 
to  a  knobby  surface ;  in  some  places  a  ledge  but  in 

others  only  scattered  boulders 2  14 

Clay  and  shale 6  20 

Sandstone,  yellow,  thicker  in  places 2  22 

Shale,  variegated   7  29 

Clay,    variegated,    very    sandy    in    part ;     carbonaceous 

streaks  near  bottom,  horizon  of  stoneware  clay 8  37 

Sandstone  ;  weathers  buff  or  with  black  coatings ;  thin- 
bedded  to  massive,  quartzose,  thickness  variable...  7  44 
Shale,  bluish  black,  with  small  lenses  of  clay;  ironstone; 

absent  in  places . 4  48 

St.  Louis  limestone,  brecciated   (top  of  Mississippian) 

The  Pottsville  has  slightly  less  than  its  average  thickness  in  the 
ahove  section.  Although  no  coal  is  shown  here,  the  formation  contains 
one  or  more  thin  coal  beds  in  most  parts  of  the  quadrangles.  All  Potts- 
ville coal  beds  are  usually  termed  "coal  Xo.  1,"  although  they  do  not 
commonly  occupy  exactly  the  same  stratigraphic  horizon  in  all  parts  of 
the  region.  Most  commonly  the  so-called  "No.  1"  lies  either  just  above 
or  just  below  the  stoneware  clay  horizon. 

Mississippian  Series 

The  uppermost  formation  of  the  Mississippian  is  the  St.  Louis 
limestone,  a  stratum  that  has  certain  peculiarities  by  which  it  may  be 
easily  identified.  As  it  marks,  where  present,  the  lower  limit  of  coal 
and  stoneware  clay,  its  detection  by  the  driller  and  the  prospector  is  of 
considerable  economic  importance.  The  St.  Louis  is  light  blue  to  brown, 
dense,  very  fine  grained,  and  has  a  more  or  less  conchoidal  fracture.  In 
this  region  its  thickness  is  25  feet  or  less.  The  St.  Louis  may  be  seen 
beneath  the  clays  mined  at  Colchester  and  at  many  other  places  in  the 
Colchester  quadrangle. 

Below  this  limestone  there  are  about  50  feet  of  blue  to  drab  shales 
intercalated  with  thin  beds  of  impure  limestone.  The  lower  third  con- 
sists of  blue  shale,  in  places  so  calcareous  as  to  be  a  homogeneous,  earthy 
limestone,  containing  many  geodes  from  the  size  of  a  marble  to  that  of 
a  football.     Since  geodes  do  not  occur  in  the  Pennsylvanian,  they  serve 


48  BIENNIAL  REPORT 

to  differentiate  the  shales  in  which  they  lie  from  very  similar  beds  in 
the  higher  series.  At  the  top  of  the  50-foot  interval  mentioned  there 
is  a  persistent  bed  of  limestone,  1  to  25  feet  thick,  that  is  so  sandy  in 
places  as  to  strongly  resemble  a  sandstone  near  the  base  of  the  Pennsyl- 
variian. 

The  oldest  and  deepest  Mississippian  rocks  exposed  belong  to  the 
Keokuk  limestone  and  consist  chiefly  of  light  to  bluish  gray  crystalline 
limestone  in  thin,  regularly  stratified  beds.  This  limestone  contains 
great  numbers  of  fossil  shells  and  irregularly  distributed  seams  and 
lenses  of  chert  or  flint.  There  are  100  feet  of  this  limestone  exposed  two 
or  three  miles  northeast  of  Plymouth,  though  only  the  upper  part  can 
be  seen  along  Brunce's  Creek  and  the  lower  parts  of  many  tributaries  as 
far  north  as  Birmingham. 

A  detailed  description  of  lower  strata  is  deferred  until  a  full  report 
on  this  region  is  published. 

STRUCTURE 

On  the  accompanying  maps  the  elevation  of  the  Murphysboro  (No. 
2)  coal  bed  above  sea  level  is  shown  by  means  of  structure  contours. 
These  contours  are  based  upon  hundreds  of  outcrop  observations  and 
on  shafts  and  well  records  over  the  quadrangles.  In  much  of  this  region 
the  coal  is  eroded  away  and  its  altitude  before  erosion  is  calculated  on 
the  assumption  that  the  vertical  distance  from  the  base  of  the  St.  Louis 
limestone  to  the  Murphysboro  coal  bed  is  75  feet  and  from  the  top  of 
the  crystalline  limestone  beds  of  the  Keokuk  to  the  coal  is  125  feet. 

The  structure  of  the  region  is  simple.  There  is  a  general  easterly 
dip  of  a  few  feet  per  mile,  but  this  is  much  modified  in  two  anticlinal 
areas  where  the  strata  have  been  arched  or  bowed  up  to  relatively  high 
levels.  In  one  of  these,  northeast  of  Plymouth,  the  horizon  of  the  coal 
is  720  feet  above  sea  level;  in  the  other,  at  Macomb,  it  is  670  feet.  In 
the  central  part  of  the  Colchester  quadrangle  the  altitude  of  the  coal 
varies  little  from  660  feet.  Faults  are  rare  and  none  of  more  than  2 
feet  vertical  displacement  was  seen  or  reported. 

OIL  AND  GAS 
Gas  in  Surface  Deposits 
Pockets  of  gas  in  sandy  portions  of  the  surface  deposits  are  quite 
common  in  Illinois,  and  several  have  been  found  in  this  region.  These 
accumulations  are  probably  derived  from  the  decomposition  of  vegetable 
matter  in  the  surface  deposits  themselves  and  do  not  have  any  necessary 
connection  with  deep-seated  oil  or  gas.     They  can  be  used  to  heat  and 


OIL  AND  GAS  IN  COLCHESTER  AND  MACOMB  QUADRANGLES  49 

light  a  few  houses,  but  the  yield  is  too  small  for  commercial  purposes. 
G.  E.  Flint  bored  two  wells  at  opposite  corners  of  his  house,  5  miles  south 
of  Colchester  (SE.  %  NE.  yA  sec.  6,  T.  4  N.,  R.  3  W.),  each  87  feet 
in  glacial  clay  and  with  sand  at  the  bottom.  Gas  came  from  the  sand 
under  considerable  pressure  and  was  used  for  cooking  and  lighting  in 
Mr.  Flint's  house  for  more  than  2  years,  until  the  wells  became  choked 
with  sand.  A  well  at  the  Price  and  Gunning  clay  plant  at  Industry  is 
reported  to  have  struck  gas  at  a  depth  of  90  feet  that  was  under  sufficient 
pressure  to  throw  mud  20  feet  into  the  air.  A  few  other  wells  in  the 
region  have  encountered  small  quantities  of  gas  at  shallow  depths,  pre- 
sumably in  surface  deposits. 

Deep  Drilling  for  Oil  and  Gas 

Encouraged  by  the  presence  of  gas  pockets  in  the  surface  deposits 
and  of  small  oil  and  gas  seepages  that  are  common  in  parts  of  the  region, 
a  company  was  formed  (several  years  ago)  to  prospect  near  Birmingham. 
Four  wells  were  drilled  within  the  limits  of  the  Colchester  quadrangle 
and  one  (No.  3)  a  short  distance  south  of  it,  between  Flower  and  Wil- 
liams creeks.  Well  No.  1  was  drilled  in  the  bottom  of  a  small  ravine 
near  Flower  Creek  (NE.  yA  SW.  %  sec.  9,  T.  3  N.,  R.  4  W.)  at  an 
altitude  of  about  530  feet.  The  St.  Peter  sandstone  was  reached  at  a 
depth  of  1,025  feet  and  continued  to  1,125  feet,  where  drilling  was  stopped. 
Mere  showings  of  oil  were  found  at  three  horizons,  said  to  be  at  depths 
of  511,  750,  and  900  feet  [the  first  is  doubtless  from  the  Hoing  sand], 
and  a  strong  flow  of  highly  mineralized  water  is  now  coming  from  the 
hole.  WTell  No.  2  was  on  the  upland  northwest  of  No.  1  (NE.  yA  NE. 
y,  sec.  8  ( ?),  T.  3  N.,  R.  4  W.)  and  was  abandoned  at  815  feet  because 
of  a  broken  casing.  Small  quantities  of  gas  are  reported.  Well  No.  4 
was  drilled  on  the  flood  plain  of  Crooked  Creek  (altitude  about  500  feet), 
three-fourths  of  a  mile  above  Birmingham  (SE.  y  NW.  y  sec.  2,  T.  3 
N.,  R.  4  W.).  One  report  is  that  drilling  was  discontinued  at  610  feet 
because  of  lost  tools.  Another  places  the  total  depth  at  482  feet.  This 
well  was  shot  at  435  feet,  near  the  base  of  a  20-foot  "oil  sand"  (this 
probably  is  above  the  Hoing  sand).  It  is  said  that  about  2  barrels  of  oil 
could  be  bailed  out  each  day.  Wrell  No.  5  is  a  short  distance  east  of  No. 
2  and  on  the  same  quarter,  at  an  altitude  of  620  feet.  Drilling  was 
stopped  in  sandstone  at  a  depth  of  1,608  feet,  with  no  signs  of  oil  or  gas. 
Water  was  found  at  60  feet  and  more  at  700  feet. 

Briefly  stated  the  conditions  essential  for  the  accumulation  of  oil 
or  gas  in  commercial  quantities  are :  ( 1 )  a  porous  stratum  in  which 
the  oil  or  gas  may  circulate;  (2)  an  impervious  cover,  commonly  a  shale. 


50  BIENNIAL  REPORT 

that  overlies  the  porous  stratum  and  prevents  the  escape  of  the  oil  or  gas 
to  the  surface;  and  (3)  rock  structure  such  that  underground  reservoirs 
are  formed.  The  first  two  conditions  are  met  in  this  region  at  several 
stratigraphic  levels.  The  rock  structure  appears  to  be  favorable  in  at 
least  one  locality.  There  are,  of  course,  in  oil  fields  many  areas  where 
all  the  conditions  appear  to  be  right,  but  where  no  oil  or  gas  exists. 

Where  the  deep-lying  rocks  are  saturated  with  water,  as  they  are  in 
this  region,  the  oil  and  gas  is  forced  upward  through  the  porous  rocks 
until  it  encounters  an  impervious  stratum.  If  the  beds  are  not  perfectly 
level,  and  usually  they  are  not,  the  oil  and  gas  move  up  the  dip  until  they 
reach  a  place  where  the  direction  of  the  inclination  changes  and  where 
continued  movement  in  any  direction  in  the  porous  stratum  would 
necessarily  be  to  lower  levels.  Under  those  conditions  accumulation 
takes  place  in  the  anticlines  or  arches,  or  at  the  upper  borders  of  dipping 
porous  areas,  where  the  porous  rocks  are  at  higher  altitudes  than  in 
adjacent  areas.  A  glance  at  the  accompanying  structure  map  (Plate  II) 
will  show  that  one  such  anticline  lies  2  miles  northeast  of  Plymouth, 
only  4  miles  northwest  of  well  No.  4  near  Birmingham. 

It  is,  perhaps,  significant  that  the  best  reported  showing  of  oil  was 
in  well  No.  4,  the  one  that  is  situated  nearest  the  crest  of  this  dome- 
shaped  anticline,  and  it  is  unfortunate  that  at  least  one  of  the  drillings 
was  not  made  in  the  more  promising  territory.  A  similar  but  less  pro- 
nounced dome  exists  near  Macomb.  The  city  water  well  at  Macomb, 
though  apparently  favorably  situated,  pierced  no  notable  quantities  of 
oil  or  gas.  The  altitude  of  the  top  of  this  well  is  700  feet,  the  depth 
to  the  top  of  the  St.  Peter  sandstone  1,135  feet,  to  its  base  1,360  feet, 
and  to  the  bottom  of  the  well  1,630  feet. 


ECONOMIC  GEOLOGY 


\Cy  of 


^CHESTER  and  MACOMB  QUADRANGLES 


N 


33 


*\ 


BY    HENRY    HINDS 


I 


U.  S.  GEOLOGICAL  SURVEY 


rr 


PLYMOUTH  OIL  FIELD 

By  Raymond   S.  Blatchley 


OUTLINE 

PAGE 

Discovery     51 

Well   records    51 

Recommendation  by  Geological  Survey 53 


DISCOVERY 


On  April  30,  1914,  oil  was  found  in  commercial  quantities  on  the 
J.  Hoing  farm  near  Plymouth,  111.,  in  the  SE.  corner  SW.  Y\  NW.  54 
sec.  16,  T.  4  N.,  R.  4  W.  The  well  is  owned  jointly  by  Snowden  Bros, 
and  the  Ohio  Oil  Company.  It  is  420  feet  deep,  and  reaches  oil  at  417 
feet  in  a  sandy  limestone  that  is  doubtfully  identified  with  the  lower  part 
of  the  Devonian  or  the  upper  part  of  the  Silurian  system. 

The  well  flows  "naturally"  and  yields  daily  about  40  barrels  of  oil 
under  a  rock  pressure  of  about  75  pounds.  Wide  attention  has  been 
attracted  to  the  well  and  as  a  result  much  excitement  prevails  in  leasing 
land  about  the  well.  Oil  men  are  excited  because  of  the  shallow  depth, 
low  cost  of  drilling,  amount  of  oil  secured,  and  the  general  attractiveness 
of  the  region  for  prospecting.  The  oil  is  green,  is  without  gas,  has  a 
gravity  of  about  37°  Beaume,  and  is  classed  as  "sweet"  because  of  the 
small  percentage  of  sulphur. 

The  successful  company  previously  drilled  two  other  wells  in  the 
same  general  locality,  having  been  attracted  by  reports  of  oil  in  a  well 
in  the  SE.  y4  NW.  %  sec.  2,  T.  3  N.,  R.  4  W.,  which  is  mentioned  later. 
The  first  well  was  started  on  the  Griggsby  farm  in  the  W.  y2  SE.  )/\ 
sec.  20,  T.  4  N.,  R.  4  W.,  on  January  30,  1914,  and  was  completed  March 
5,  1914.  It  was  abandoned  at  a  depth  of  805  feet  after  a  showing  of  5 
gallons  of  oil  at  425  to  432  feet  in  the  same  formation  that  now  produces 
in  the  Hoing  well.  The  second  well  was  drilled  shortly  afterwards  on 
the  Collins  farm  in  the  E.  y2  SE.  Y\  of  the  same  section.  It  was  drilled 
to  444  feet,  and  obtained  a  showing  of  oil  at  421  and  439  feet.  It  was 
abandoned. 

WELL  RECORDS 

The  records  of  recent  wells  are  published  with  permission  of  the 
operators. 

(51) 


52 


BIENNIAL  REPORT 


Log  of  Hoing  well  No.  1,  SE.  cor.  SW.  YA  NW .  Y±  sec.  16,  T.  4  N.,  R.  4  W. 

Elevation — 510  feet 
(Interpretation  by  T.  E.  Savage  and  R.  S.  Blatchley) 

Thickness  Depth 

Surface  deposits —  Feet  Feet 

Soil  and  clay  15  15 

Quicksand  and  gravel 72  87 

Carboniferous  system — 
Mississippian  series — 

St.  Louis  and  Osage  groups — 

Limestone,  gray  73  160 

Kinderhook  and  Upper  Devonian  shales — 

Slate   and   shale 120  280 

Shale,  brown  25  305 

Slate  and  shale,  white 92  397 

Devonian   (?)    system — 

Hamilton  (?)  limestone — 

Limestone,   gray,   becoming   sandy   at   base,    oil, 

417    feet....' 23  420 

Log  of  Collins  well  No.  1,  E.  y2  SE.  Ya  sec.  20,  T.  4  N.,  R.  4  W. 
Elevation— 588  feet 
(Interpretation  by  R.  S.  Blatchley) 
Surface  deposits — 

Soil   and   clay 19  19 

Carboniferous  system — 
Mississippian  series — 

St.  Louis  and  Osage  groups — 

Limestone     82  101 

Limestone,    sandy    55  156 

Limestone,  white   35  191 

Kinderhook  and  Upper  Devonian  shales — 

Mud,  white,  and  shale 30  221 

Shale,  brown   10  231 

Shale,    white    41  272 

Shale,  brown 12  284 

Shale,  blue  36  320 

Mud,  white    25  345 

Slate,  gray  20  365 

Shale,  brown   20  385 

Mud,  white   11  396 

Devonian  (?)  system — 

Hamilton   (?)   limestone — 

Limestone,  broken   10  406 

Limestone,  show  of  oil  at  421  and  439  feet 38  444 


PLYMOUTH  OIL  FIELD  53 

Log  of  Griggsby  well  No.  1,  W.  V2  SE.  %  sec.  20,  T.  4  N.,  R.  4  W. 

Elevation — 576  feet 

(Interpretation  by  R.  S.  Blatchley) 

Thickness  Depth 

Surface  deposits —                                                                                Feet  Feet 

Soil   and   clay 26  26 

Carboniferous  system — 
Mississippian  series — 

St.  Louis  and  Osage  groups — 

Limestone,  gray   10  36 

Mud   10  46 

Limestone,  white,  sandy 44  90 

Limestone,  gray,  water  at  115  feet 55  145 

Limestone,  white    35  180 

Kinderhook  and  Upper  Devonian  shales — 

Mud,  white    , 30  210 

Shale,  brown  '. 10  220 

Slate,  white,  and  mud 40  260 

Shale,  brown  10  270 

Slate,  white,  and  shale 20  290 

Mud,  white    21  311 

Slate,  white,  sandy  67  378 

Shale,  brown  7  385 

Slate,  white,  sandy 15  400 

Devonian  and  Silurian  systems  (?)  — 

Limestone,  gray,  show  of  oil  425  to  432  feet 34  434 

Ordovician  system — 

Richmond  (Maquoketa)   shale — 

Slate   and   shale 91  525 

Kimmswick-Plattin   (Trenton)   limestone — 

Limestone,  broken  96  621 

Limestone,  white   29  650 

Limestone,  brown    155  805 

RECOMMENDATION  BY  GEOLOGICAL  SURVEY 

The  finding  of  oil  in  this  region  is  of  special  interest  because  of 
previous  recommendations  in  a  geological  report  prepared  in  1913  by 
Henry  Hinds  of  the  U.  S.  Geological  Survey  in  co-operation  with  the 
Illinois  State  Geological  Survey.  This  report  has  been  delayed  in  pub- 
lication but  the  preceding  extract  from  it,  with  an  illustration,  is  hastily 
published  at  this  time  as  an  aid  in  scientific  development  of  the  oil  possi- 
bilities in  this  region. 


GEOLOGY  OF  THE  LA  SALLE  AND 
HENNEPIN  QUADRANGLES 

By  Gilbert  H.  Cady 


OUTLINE 

PAGE 

Introduction    55 

Character  of  investigations 55 

Topographic  maps    56 

Geologic  maps  57 

Topography     59 

Stratigraphy 59 

Glacial  deposits   59 

"Coal    Measures"    60 

La  Salle  anticline    60 

Economic   geology    61 

Sand  and  gravel 61 

Coal     62 

Clays     62 

Portland  cement  rock 63 

Natural-cement  rock   : .  63 

Glass   sand    63 

Artesian   water    63 

Scenic  features    65 

ILLUSTRATIONS 
Figure 

2.  Map  of  area  of  La  Salle  and  Hennepin  quadrangles  showing  posi- 

tion of  moraines  and  locations  of  artesian  wells 58 

3.  Diagram  showing  structure  across  La  Salle  anticline 60 


INTRODUCTION 
Character  of  Investigations 
The  State  Geological  Survey  has  in  preparation  final  geological 
reports  and  maps  for  the  La  Salle  region  which  will  be  published  in 
cooperation  with  the  U.  S.  Geological  Survey.  The  present  brief  state- 
ment reviews  the  progress  and  methods  of  work  and  summarizes  in 
popular  language  the  more  important  features  of  the  geology  and  min- 
eral resources. 


(55) 


56 


BIENNIAL  REPORT 


Topographic  Maps 

The  geologic  work  is  based  on  topographic  maps  of  the  La  Salle 
and  Hennepin  quadrangles,  already  published.  These  are  parts  of  a 
topographic  map  of  the  entire  State,  and  of  the  United  States,  which 
is  being  prepared  in  units  measuring  about  12  by  18  miles  and  con- 
taining about  225  square  miles  each.  The  quadrangles  are  bounded 
by  parallels  and  meridians,  and  so  do  not  regard,  or  conform  to,  civil 
boundaries.  The  scale  of  the  maps  is  1  :62500,  or  about  1  mile  to  the 
inch.  The  features  represented  on  the  topographic  map  are  of  three 
kinds:  (1)  inequalities  of  surface,  called  relief,  as  plains,  valleys, 
hills;  (2)  distribution  of  water,  called  drainage,  as  streams,  lakes, 
and  swamps;  (3)  works  of  man,  called  culture,  as  roads,  railroads, 
boundaries,  villages,  cities,  and  houses. 

In  certain  states  that  have  geological  surveys,  including  Illinois, 
the  preparation  of  the  maps  is  carried  out  by  state  and  federal  bureaus 
in  cooperation,  and  the  results  are  engraved  in  final  form  by  the  United 
States  Geological  Survey.  The  survey  of  the  topography  precedes  that 
of  the  geology  by  usually  one  or  more  years ;  hence,  many  more  areas  have 
been  mapped  topographically  than  geologically.  A  number  of  maps 
in  the  following  list  of  those  for  northern  Illinois,  have  interest  for 
people  in  the  La  Salle-Hennepin  region. 


Northwestern  Illinois- 
Galena 
Elizabeth 
Savanna 
Cordova 
Clinton 
LeClaire 
Joslyn 
Milan 

Northeastern  Illinois— 
Waukegan 
Highwood 
Evanston 
Wheaton 
Riverside 
Chicago 
Desplaines 
Calumet 


Chicago  geologic  folio 


Illinois  Valley — 

Joliet 

Wilmington 

Morris 

Marseilles 

Ottawa 

La  Salle 

Hennepin 

Lacon 

Dunlap 

Metamora 

Peoria 

Central  Illinois — 
Canton 
Colchester 
Tallula 
Lincoln 
Springfield 
Mahomet 
Urbana 
Danville 


GEOLOGY  OF  THE  LA  SALLE  AND  HENNEPIN  QUADRANGLES  57 

These  maps  can  be  obtained  for  10  cents  each  from  the  Director 
of  the  State  Geological  Survey,  Urbana,  111.,  or  from  the  Director  of 
the  U.  S.  Geological  Survey,  Washington,  D.  C.  The  topographic  maps 
of  the  La  Salle  and  Hennepin  quadrangles  were  published  in  1911  to 
replace  a  poorer  edition  of  1893. 

Geologic  Maps 

Final  geologic  maps  are  published  in  folios  along  with  topographic 
maps  and  geological  reports,  but  are  not  distributed  separately  as  are 
the  topographic  maps.  Geologic  maps  represent  the  character  and  dis- 
tribution of  the  rocks  at  the  surface,  by  colors  and  conventional  signs 
printed  on  the  topographic  base  map.  Underground  relations  of  the 
rocks  are  shown  so  far  as  known  by  means  of  structure  sections  and 
contours,  and  in  such  detail  as  the  scale  permits.  Such  maps  are  of 
several  kinds :  ( 1 )  the  areal  geology  maps  show  the  areas  underlain 
by  the  various  formations;  (2)  the  economic  geology  map  represents 
the  distribution  of  useful  minerals  and  rocks  and  shows  their  relations 
to  the  topographic  features  and  to  geologic  formations;  (3)  if  there 
are  important  mining  industries  or  artesian  basins  in  the  area,  special 
maps  to  show  these  features  are  included  in  the  folio. 

The  geologic  investigation  in  preparation  for  the  text  of  the  La  Salle- 
Hennepin  folio  has  been  carried  on  during  the  summers  of  1910-12 
by  Professor  U.  S.  Grant  and  Mr.  G.  H.  Cady  of  the  State  Geological 
Survey  in  cooperation  with  the  federal  survey.  The  work  of  Dr.  Grant 
has  been  confined  largely  to  the  Hennepin  area,  and  that  of  Mr.  Cady 
to  the  La  Salle  area.  The  folio  report  on  these  two  quadrangles  is  now 
in  preparation.  An  earlier  report  on  the  cement  materials  at  and  near 
La  Salle  was  prepared  by  Mr.  Cady  some  years  ago1.  In  obtaining 
data  for  the  preparation  of  the  new  geologic  maps  and  reports  all 
possible  sources  of  information  were  used.  The  geologist  has  aimed  to 
examine  all  outcrops  along  streams  and  roads.  Practically  every  mine 
in  the  area  has  been  visited ;  logs  of  nearly  all  the  deep  wells,  and  sam- 
ples of  drillings  from  several,  besides  the  records  of  a  large  proportion 
of  the  coal  borings  have  been  collected  through  the  cooperation  of  the 
owners.  The  published  data  excludes  certain  confidential  information, 
but  in  general  terms  records  the  results  of  all  information  at  hand. 
Only  on  such  a  policy  can  be  based  the  hope  that  future  work  in  neigh- 
boring localities  will  receive  generous  support  from  the  operators,  as  in 
this  area. 


1Cady,  G.   H.,  Cement-making  materials  in  the  vicinity  of  La  Salle:     111.   State  Geol.   Sur- 
vey Bull.   8,   p.    127,    1908. 


58 


BTENNIAL  REPORT 


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GEOLOGY  OF  THE  LA  SALLE  AND  HENNEPIN  QUADRANGLES  59 

The  results  of  the  investigation  in  the  two  quadrangles  are  here  briefly 

summarized : 

TOPOGRAPHY 

The  surface  of  the  quadrangles  is  in  general  a  level  plain,  but  it  is 
relieved  by  two  kinds  of  irregularities.  The  most  evident  of  these  is 
the  valley  of  the  Illinois  with  its  tributaries ;  the  other  consists  of 
three  ridges,  or  lines  of  small  knolls  rising  above  the  plain.  One  lies 
between  Pecumsaugan  and  Tomahawk  creeks ;  the  other  two  are  united 
in  the  hilly  country  around  Arlington,  but  at  that  location  separate  so  that 
a  branch  continues  southwest  through  Dover  and  Princeton  and  reap- 
pears possibly  in  the  high,  rolling  land  south  of  Bureau  Creek.  The 
second  spur  lies  between  Brush  Creek  and  East  Bureau  Creek  and  dies 
out  abruptly  in  the  vicinity  of  Coal  PIollow  (fig.  2). 

The  upland  landscape  is  one  resulting  from  glaciation,  the  plains 
being  underlain  by  gravel  or  bowlder  till ;  the  ridges,  known  as  moraines, 
are  composed  in  the  main  of  bowlder  clay.  The  valley  features  are 
developed  in  glacial  deposits  in  places,  and  are  due  to  the  erosion  of 
hard  rocks  elsewhere.  The  valleys  in  the  La  Salle  quadrangle  are  com- 
monly cut  into  rock. 

STRATIGRAPHY 
Glacial  Deposits 

Glacial  deposits  of  the  area  consist  of  three  layers  of  clay,  hardpan, 
sand,  or  gravel  overlying  one  another,  especially  in  the  Hennepin  quad- 
rangle. They  differ  so  in  character  that  they  resulted  probably  from 
three  distinct  ice  invasions.  Between  these  three  layers  of  glacial  mate- 
rial are  two  interglacial  soil  beds,  composed  in  places  of  a  thick  layer 
of  partly  decayed  twigs  and  branches.  Such  layers  probably  furnish 
much  of  the  gas  occurring  in  the  vicinity  of  Princeton.  The  altitude 
of  these  forest  beds  is  about  525  and  620  feet  above  sea  level. 

The  surface  upon  which  the  glacial  material  was  deposited  drained 
toward  a  deep  valley  which  ran  parallel  with  the  west  edge  of  the 
Hennepin  quadrangle  in  the  vicinity  of  Princeton  and  continued  north- 
ward toward  the  Rock  River  valley.  The  present  Illinois  River  occu- 
pies the  older,  partly  filled  valley  below  the  bend  at  Bureau.  The  alti- 
tude of  the  bottom  of  the  old  valley  was,  so  far  as  present  records 
show,  about  325  feet  above  sea  level.  The  present  Illinois  Valley 
apparently  did  not  exist  before  the  glacial  period,  certainly  not  that 
part  of  the  valley  above  Bureau.  In  the  vicinity  of  Cedar  Point  and 
Standard  there  was  a  tributary  valley   draining  toward  the   southwest 


60  BIENNIAL  REPORT 

but  extending  from  the  north  across  the  present  valley  of  the  Illinois 
east  and  west  of  Spring  Valley,  and  from  the  northeast  towards  Oglesby 
and  possibly  even  toward  Utica.  Another  valley  ran  from  east  to  west 
in  the  center  of  the  Hennepin  quadrangle,  draining  from  the  direction 
of  Dimmick. 

"Coal  Measures" 

The  Upper  Carboniferous  rocks  or  "Coal  Measures"  in  Illinois  are 
separated  into  three  formations.  The  Pottsville  formation  includes  all 
strata  below  the  bottom  of  coal  No.  2  or  the  "third  vein  coal."  In  this 
region  the  formation  has  a  maximum  thickness  of  about  250  feet,  with 
a  minimum  of  from  4  to  5  feet.  The  Carbondale  formation  embraces 
strata  from  the  base  of  coal  No.  2  to  the  top  of  coal  No.  6  or  the  "blue- 
band  coal."  This  latter  coal  being  absent  in  this  region,  the  top  of  the 
Carbondale  formation  probably  lies  at  the  base  of  a  heavy  sandstone 
layer  occurring  between  coal  No.  5  and  coal  No.  7,  or  the  second  and 
first  veins,  and  locally  cutting  out  the  middle  coal  entirely.  The  thick- 
ness of  the  formation  averages  about  200  feet.     The  McLeansboro  for- 


5= 


Fig.  3. — Diagram  showing  structure  across   La  Salle  anticline. 

mation  includes  the  remainder  of  the  "Coal  Measures"  strata,  and  in  it 
are  the  upper  coal  bed  and  the  La  Salle  limestone.  The  maximum 
thickness  of  this  formation  on  the  quadrangle  is  about  400  feet.  The 
total  thickness  of  the  "Coal  Measures"  on  the  quadrangles  is  between 
850  and  900  feet. 

LA  SALLE  ANTICLINE 

The  hard-rock  geology  of  the  region  is  complicated  by  a  prominent 
deformation  of  the  strata  whereby  the  beds  on  the  west  side  of  a  line 
running  diagonally  from  the  northwest  corner  to  the  southeast  corner 
of  the  La  Salle  quadrangle  are  downfolded,  so  that  they  lie  at  a  much 
lower  altitude  than  the  same  strata  on  the  east.  The  line  of  pronounced 
deformation  is  known  as  the  La  Salle  anticline.  The  inclination  of  the 
beds  along  the  fold  is  well  exposed  at  Split  Rock,  Little  Rock,  Deer  Park, 
and  at  other  places  up  the  Vermilion  rivers  (fig.  3). 

On  the  north  side  of  Illinois  River  the  bed  rock  east  of  the  fold  is 
sandstone  known  as  the  St.  Peter  sandstone,  and  farther  north  lime- 
stone known  as  the  Galena-Trenton  limestone.     Between  Utica  and  Split 


GEOLOGY  OF  THE  LA  SALLE  AND  HENNEPIN  QUADRANGLES  61 

Rock  along  Illinois  River  and  in  limited  areas  along  Little  Vermilion 
River  and  Tomahawk  and  Pecumsaugan  creeks  the  Lower  Magnesian 
limestone  comes  to  the  surface.  This  latter  is  the  oldest  outcropping 
stratum  in  the  State.  South  of  the  river  and  east  of  the  fold  the 
"Coal  Measures,"  although  thin,  cover  up  the  older  strata  except  along 
certain  streams  which  have  cut  into  the  underlying  rock,  as  at  Deer 
Park  and  various  places  along  Vermilion  River. 

East  of  the  fold  the  bed  rock  is  all  of  Carboniferous  age,  and  is 
commonly  known  as  the  "Coal  Measures."  Between  the  elevation  of 
corresponding  strata  of  the  "Coal  Measures"  east  and  west  of  the  fold, 
within  a  distance  of  about  one-half  mile,  there  is  a  difference  of  altitude 
of  about  500  feet.  Between  the  altitude  of  the  top  of  the  St.  Peter 
sandstone  east  and  west  of  the  fold  there  is  a  difference  of  about  1,500 
feet;  thus,  west  of  the  fold  there  occurred  between  the  St.  Peter  sand- 
stone and  the  "Coal  Measures"  about  one  thousand  feet  of  strata  not 
found  to  the  east.  The  deep  wells  in  La  Salle  and  Peru  pass  through 
the  Niagara  limestone,  the  Cincinnati  shale,  and  the  Galena-Trenton 
limestone  after  penetrating  the  "Coal  Measures"  and  before  reaching 
the  St.  Peter  sandstone.  West  of  the  line  of  deformation  this  succession 
of  strata  continues  to  and  beyond  the  edge  of  the  Hennepin  quadrangle, 
with  only  a  slight  gradual  elevation  toward  the  west.  This  elevation 
toward  the  west  affects  the  "Coal  Measures"  rather  more  than  the  under- 
lying beds,  so  that  probably  the  different  coal  beds  outcrop  underneath 
the  drift  before  Princeton  is  reached,  though  the  "third  vein"  coal 
probably  extends  to  the  west  edge  of  the  quadrangle  in  the  vicinity  of 
Tiskilwa. 

ECONOMIC  GEOLOGY 
Sand  and  Gravel 
The  sand  and  gravel  deposits  of  the  area  represent  important  eco- 
nomic assets.  They  are  best  developed  along  the  Illinois  in  the  vicinity  of 
La  Salle,  Spring  Valley,  between  Depue  and  Bureau,  and  in  the  area 
known  as  the  Hennepin  terrace.  These  deposits,  except,  perhaps,  the 
Hennepin  terrace,  are  probably  of  about  the  same  age  as  the  latest  drift 
sheet  of  the  area,  that  is,  "Early  Wisconsin,"  and  occupy  depressions 
in  the  underlying  glacial  debris  or  in  the  bed  rock.  Numerous  lenses 
and  beds  of  gravel,  generally  wide-spread,  occur  near  the  two  forest 
beds  and  afford  ample  source  of  water  for  great  numbers  of  farm  wells, 
100  to  250  feet  deep,  especially  east  of  the  two  Vermilion  rivers.  Lenses 
of  gravel  in  the  upper  till  sheet  afford  water  for  shallow  wells,  as  in 
the  vicinity  of  Triumph. 


62 


BIENNIAL  REPORT 


Coal 

Coal  No.  2  or  the  "third  vein  coal"  is  the  one  most  commonly  mined 
in  the  area.  It  averages  135  feet  below  the  "second  vein  coal"  or  coal 
No.  5,  which  is  now  mined  only  by  the  Matthiessen  &  Hegeler  Zinc  Co. 
The  "first  vein  coal,"  or  coal  No.  7,  averages  about  45  feet  above  the 
"second  vein"  and  is,  at  present,  known  only  from  outcrop.  It  has,  how- 
ever, been  mined  until  recently  in  Rocky  Run  near  Tiskilwa.  The  "third 
vein"  averages  about  42  inches  in  thickness.  It  preserves  its  average 
thickness  very  uniformly  over  wide  areas.  The  "second  vein"  is  variable 
in  thickness  up  to  72  inches,  and  averages  about  42^  inches.  The  "upper 
vein"  averages  about  39  inches,  but  like  the  "middle  vein"  it  is  more 
variable  than  the  "third  vein"  coal. 

The  character  of  the  coal  is  shown  by  the  analyses  in  the  accompany- 
ing table.  For  the  sake  of  comparison  a  table  showing  the  unit  coal 
averages  for  various  Illinois  coals  is  introduced  from  Bulletin  No.  16, 
State  Geological  Survey  (p.  213). 

Analyses  of  samples  of  coal  No.  2  "as  received'"  from  La  Salle  and  Hennepin 

quadrangles 


La  Salle  County 


Lab.  No. 
4067 


Lab.  No. 
4064 


Bureau   County 


Putnam    County 


Lab.  No. 
1771 


Lab.  No.      Lab.  No.      Lab.  No. 
4070  2617  4072 


Moisture    

Volatile    matter 

Fixed    carbon 

Ash     

Sulphur     

British    thermal    units 

Ash,     water     and     sulphur 
free  unit  coal 


13.06 

13.71 

13.13 

16.62 

16.00 

39.21 

39.56 

38.60 

36.56 

36.19 

38.02 

39.13 

37.67 

37.29 

38.05 

9.71 

7.60 

10.60 

9.53 

9.76 

4.17 

3.76 

3.61 

2.94 

2.96 

11220 

11439 

10897 

10725 

10781 

14845 

14800 

14524 

14798 

14726 

15.20 
37.00 
38.77 
9.03 
3.81 
10937 

14731 


Clays 

Included  in  the  "Coal  Measures"  are  numerous  beds  of  shale  or 
clay  of  economic  value.  These  are  notably  ( 1 )  the  clay  occurring  below 
coal  No.  2  at  Deer  Park,  Black  Hollow,  Lowell,  and  south  of  Utica 
along  Illinois  River,  being  probably  the  same  age  as  the  well-known 
Cheltenham  clays  of  St.  Louis ;  (2)  the  clay  below  coal  No.  7  or  the  "first 
vein"  coal  mined  at  the  Matthiessen  &  Hegeler  mine  at  La  Salle;  (3)  the 
clay  above  the  La  Salle  limestone  worked  in  the  ravine  between  La  Salle 
and  Peru.  Other  beds  of  clay  or  shale  of  economic  value  doubtless  occur 
in  the  "Coal  Measures"  but  none  but  those  mentioned  are  used  at  present. 


geology  of  the  la  salle  and  hennepin  quadrangles  63 

Portland  Cement  Rock 

The  La  Salle  limestone  is  another  important  bed  of  the  "Coal  Meas- 
ures" in  this  locality.  The  limestone  is  an  important  scenic  feature  in  the 
vicinity  of  La  Salle  and  Oglesby  along  both  Vermilion  rivers,  forming 
abrupt  cliffs  25  to  30  feet  high.  In  the  vicinity  of  the  anticline  where 
the  strata  are  uptilted,  this  ledge  of  rock  tends  to  come  to  the  surface,  and 
where  not  covered  by  glacial  debris  too  deeply  forms  a  ridge  or  hogback, 
such  as  that  to  be  observed  on  the  Utica  road  about  one  mile  east  of 
La  Salle.  The  best  conception  of  the  character  of  the  fold  follows  a 
study  of  the  inclination  of  the  La  Salle  limestone. 

The  economic  value  of  the  rock  arises  from  its  thickness  and  its 
purity  as  a  lime  carbonate,  making  it  suitable  for  the  manufacture  of 
Portland  cement.  Three  large  plants  are  at  present  engaged  in  this 
industry. 

The  La  Salle  limestone  averages  about  30  feet  in  thickness.  It  is 
separated  into  two  beds  by  a  layer  of  clay  of  varying  thickness  about 
one-third  the  way  from  the  bottom.  The  base  of  the  limestone  is 
marked  by  a  black  fissile  shale  or  "slate,"  an  horizon  which  can  be 
traced  over  wide  areas  of  the  La  Salle  quadrangle.  The  typical  cement- 
making  limestone  is  limited  in  extent  to  a  strip  about  one  mile  wide 
running  along  the  two  Vermilion  rivers  from  near  Bailey's  Falls  on 
the  south  to  a  little  north  of  the  mouth  of  Tomahawk  Creek  on  the 
north.  To  the  west,  the  limestone  changes  character,  becoming  useless 
as  cement-making  material. 

Natural-cement  Rock 

The  raw  material  for  the  production  of  natural  cement  occurs  in  two 
beds  in  the  Lower  Magnesian  limestone  which  outcrops  between  Utica 
and  Split  Rock.  These  beds  are  about  20  feet  apart,  the  upper  one 
about  8  feet  thick,  and  the  lower  one  varying  from  8  to  20  feet.  At 
present  the  rock  is  worked  only  in  the  Illinois  Valley  west  of  Utica. 
Former  mine  openings,  however,  are  conspicuous  features  of  the  cliff 
along  the  Rock  Island  road  west  of  Utica. 

Glass  Sand 

Another  stratum  of  economic  interest  is  the  St.  Peter  sandstone 
which  between  La  Salle  and  Ottawa  is  extensively  quarried  for  glass  sand. 

Artesian  Water 

Three  different  areas  of  artesian  water  appear  on  the  quadrangle: 

(1)     The  wells  near  Utica  and  at  Deer  Park  obtain  their  water  at  a 

depth  of   150  and  200   feet  from  the  sandstone  underlying  the  Lower 


64 


BIENNIAL  REPORT 


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GEOLOGY  OF  THE  LA  SALLE  AND  HENNEPIN  QUADRANGLES  65 

Magnesian  limestone  which  is  exposed  at  the  surface.  This  sandstone 
is  not  to  be  confused  with  the  higher  St.  Peter  sandstone,  from  which 
it  is  separated  by  an  interval  of  from  100  to  150  feet. 

(2)  The  wells  west  of  the  fold,  including  those  at  La  Salle,  Port- 
land, Cedar  Point,  and  Depue,  obtain  most  of  their  water  from  the 
Galena-Trenton  limestone  and  St.  Peter  sandstone  at  a  depth  of  from 
1,200  to  1,700  feet.     The  Princeton  well  belongs  to  this  group. 

(3)  The  wells  at  Bureau  and  Hennepin  and  west  along  Bureau 
Creek  obtain  water  from  the  Niagara  or  Devonian  limestone  at  a  depth 
of  from  500  to  850  feet.  The  analyses  of  the  water  of  several  of  these 
wells  were  recently  completed  by  the  State  Water  Survey  and  are  shown 
in  the  accompanying  table. 

SCENIC  FEATURES 

Importance  should  be  attached  to  the  scenic  value  of  certain  topo- 
graphic features,  such  as  the  cliffs  of  St.  Peter  sandstone  along  the 
south  bluff  of  Illinois  River  and  at  Deer  Park,  and  those  of  the  La  Salle 
limestone  along  the  Vermilion  near  Bailey's  Falls.  Other  localities,  on 
a  somewhat  smaller  scale,  are  rather  common  along  the  Little  Vermilion 
River  and  on  the  south  bluff  of  Illinois  River  west  of  La  Salle  and 
between  Split  Rock  and  Utica,  especially  in  the  vicinity  of  Pecumsau- 
gan  Creek.  An  extension  of  the  boundaries  of  the  present  State  Park 
at  Starved  Rock  to  embrace  the  natural  features  extending  along  the 
south  bluff  of  Illinois  River  for  miles  is  an  enterprise  worthy  of  thought- 
ful consideration. 


(1912-3m> 

NOTICE 

To  be  inserted  between  pages  66  and  67,  Bulletin  23, 
Illinois  State  Geological  Survey 


This  paper  is  a  reprint  from  the  same  plates  e#  the  extract 
from  Bulletin  23,  published  in  November,  1913.  The  first  publi- 
cation of  the  new  species  of  fossils  noted  herein  was  in  this  ex- 
tract that  was  distributed  in  November,  1913. 


Earlier  studies  and  interpretation  of  the  strata 69 

Stratigraphy    72 

General  stratigraphic  relations 72 

Thickness  and  formations  of  the  series 73 

Girardeau   limestone 73 

Occurrence  and  stratigraphic  relations 73 

Detailed   section 73 

Edgewood   limestone 75 

Occurrence  and  stratigraphic  relations 75 

Detailed  sections   77 

Channahon  limestone  member 84 

Essex  limestone 86 

Occurrence  and  stratigraphic  relations 86 

Detailed  section 86 

Sexton  Creek  (Brassfield)   limestone 87 

Occurrence  and  stratigraphic  relations 87 

Detailed  sections  88 

General    conclusions 91 

Paleontology  of  the  Girardeau  and  Edgewood  limestones 95 

Introductory  statement 95 

Descriptions  of  species  from  the  Girardeau  limestone 95 

Descriptions  of  species  from  the  Edgewood  formation 113 

Fossils  from  the  Channahon  limestone  member 149 


PLATES 
Fossils  from  the  Alexandrian  series 161 


1Part   II   of  this  series,  dealing  with  the   stratigraphy  and  paleontology  of  the   Essex   and 
Sexton   Creek  limestones,  is  in  preparation. 

(67) 


STRATIGRAPHY  AND  PALEONTOLOGY  OF  THE 

ALEXANDRIAN  SERIES  IN  ILLINOIS 

AND  MISSOURI 

PART    I1 
By  T.  E.  Savage 


OUTLINE 

PAGE 

Introduction    68 

Distribution  of  strata 69 

Earlier  studies  and  interpretation  of  the  strata 69 

Stratigraphy    72 

General  stratigraphic  relations 72 

Thickness  and  formations  of  the  series 73 

Girardeau   limestone 73 

Occurrence  and  stratigraphic  relations 73 

Detailed   section 73 

Edgewood   limestone 75 

Occurrence  and  stratigraphic  relations 75 

Detailed  sections   77 

Channahon  limestone  member 84 

Essex  limestone 86 

Occurrence  and  stratigraphic  relations 86 

Detailed   section 86 

Sexton  Creek   (Brassfield)   limestone 87 

Occurrence  and  stratigraphic  relations 87 

Detailed  sections  88 

General    conclusions 91 

Paleontology  of  the  Girardeau  and  Edgewood  limestones 95 

Introductory  statement 95 

Descriptions  of  species  from  the  Girardeau  limestone 95 

Descriptions  of  species  from  the  Edgewood  formation 113 

Fossils  from  the  Channahon  limestone  member 149 


PLATES 
Fossils  from  the  Alexandrian  series 161 


1Part   II   of  this  series,   dealing  with  the   stratigraphy  and  paleontology  of  the   Essex   and 
Sexton  Creek  limestones,  is  in  preparation. 

(67) 


68  BIENNIAL   REPORT 

INTRODUCTION 

The  name  Alexandrian  series2  was  proposed  by  the  writer  in  1908, 
in  order  to  provide  a  place  for  the  early  Silurian  strata  occurring  in  Illi- 
nois and  eastern  Missouri  which  occupy  a  position  above  the  top  of  the 
generally  accepted  Cincinnatian  (Richmond)  and  below  the  Brassfield 
(Ohio  Clinton)  limestone. 

Regarding  the  stratigraphic  position  of  the  Brassfield,  Professor 
Schuchert3  states  in  his  classic  work  on  the  paleogeography  of  North 
America  that  "in  the  Anticosti  section  it  is  seen  that  this  so-called  Clinton 
(Ohio  Clinton)  or  Triplecia  ortoni  zone,  is  older  than  the  true  Clinton  of 
the  Appalachian  region."  It  is  now  also  known  that  the  fauna  of  the 
Brassfield  limestone  is  very  closely  allied  to  that  of  the  earlier  Silurian 
strata  of  Illinois  and  eastern  Missouri,  as  shown  in  the  similarity  of  sev- 
eral of  the  genera  and  species  to  those  of  the  older  Edgewood  limestone. 
For  this  reason,  the  strata  representing  the  Brassfield  in  Illinois  and  Mis- 
souri are  here  included  in  the  Alexandrian  series. 

As  now  defined,  the  Alexandrian  series  embraces  all  the  strata  in 
this  region  between  the  top  of  the  Cincinnatian  (Richmond)  and  the  top 
of  the  Brassfield  limestone.  It  includes  strata  that  have  been  referred  to 
in  the  literature  under  various  formation  names ;  as  the  Girardeau  lime- 
stone, Bowling  Green  limestone,  Noix  oolite,  Edgewood  limestone,  Sexton 
Creek  limestone,  Channahon  limestone,  and  Essex  limestone.  Some  of 
these  strata  have  been  assigned  to  positions  in  the  geologic  column  as 
widely  separated  as  the  Trenton  division  of  the  Ordovician,  and  the 
Onondaga  of  the  Devonian  system. 

In  1857  Billings  proposed  the  name  Middle  Silurian — "Anticosti 
group"4 — for  the  succession  of  strata  exposed  on  the  island  of  Anticosti, 
in  the  Gulf  of  St.  Lawrence.  In  the  lower  part  of  his  Anticosti  group, 
Billings  included  the  representatives  of  Ordovician  strata  to  which  the 
name  Richmond  has  since  been  applied ;  in  the  upper  part  were  included 
strata  equivalent  to  the  entire  Niagaran  series  of  the  New  York  section ; 
and  in  the  middle  portion  were  strata  belonging  to  the  interval  between 
the  Richmond  below  and  the  Niagaran  (New  York  Clinton)  above,  to 
which  has  been  given  the  name  Alexandrian  series.  Since  the  Anticosti 
group,  as  defined  by  Billings,  embraced  at  the  base  so  important  a  part  of 
the  Cincinnatian  series  as  the  Richmond,  and  in  the  upper  part  the  whole 
of  the  Niagaran  series,  this  term  is  not  considered  appropriate  or  in  any 
sense  to  have  priority  as  a  name  for  only  that  portion  of  the  Anticosti  SeC- 


^avage,  T.  E.,  Am.  Jour.   Sci.  4th  ser.  vol  25,  p.  434,  1908. 

''Schuchert,     Charles,     Paleogeography     of     North     America:      Geol.      Soc.     America,     vol. 
20,  p.   538,   1910. 

■T.illings,    E.,    Can.    Geol.    Survey:      Report   of  progress,   pp.    247-255,    1857. 


ALEXANDRIAN  SERIES  69 

tion  belonging  to  the  interval  between  the  Richmond  of  the  Ordovician 
and  the  New  York  Clinton  of  the  Silurian  to  which  the  name  Alexandrian 
series  has  been  applied. 

DISTRIBUTION  OF  STRATA 

The  rocks  representing  the  Alexandrian  series  in  Illinois  and  eastern 
Missouri  appear  at  the  surface  in  two  general  areas  separated  by  a  dis- 
tance of  200  miles.  One  area  borders  both  sides  of  Mississippi  River 
from  about  the  mouth  of  Ohio  River,  north  nearly  to  Hannibal,  Missouri. 
Within  this  belt  outcrops  occur  at  intervals  over  a  width  of  25  to  40 
miles.  Good  exposures  have  been  studied  in  Alexander  and  Union  coun- 
ties, Illinois,  and  in  the  vicinity  of  Cape  Girardeau,  Missouri.  Xorth  of 
the  fault  line  that  crosses  the  south  end  of  Jersey  and  Calhoun  counties, 
Illinois,  and  west  into  Lincoln  County,  Missouri,  strata  representing  some 
part  of  this  series  outcrop  at  a  number  of  places  over  the  east  part  of 
Lincoln,  Pike,  and  Ralls  counties,  Missouri,  and  in  Jersey,  Calhoun,  and 
Pike  counties,  Illinois,  within  a  distance  of  12  to  20  miles  from  the 
Mississippi. 

The  second  area  in  which  these  early  Silurian  rocks  are  exposed  in 
the  upper  Mississippi  valley  is  in  Will  and  Kankakee  counties  in  north- 
eastern Illinois,  where  somewhat  isolated  outcrops  of  the  Sexton  Creek 
(Brassfield)  limestone  and  earlier  Silurian  strata  appear  at  a  number  of 
places  in  the  vicinity  of  Kankakee  and  Desplaines  rivers.  It  is  proba- 
ble that  the  Alexandrian  strata  in  the  Mississippi  River  area  and  in 
northeast  Illinois  are  more  or  less  continuous,  probably  along  the  present 
basin  of  the  Illinois  River,  but  they  are  concealed  beneath  younger  deposits 
in  the  intervening  region. 

EARLIER  STUDIES  AXD  INTERPRETATIONS  OF  THE 

STRATA 

In  a  report  in  1855,  Air.  G.  C.  Swallow,5  who  was  then  State  Geol- 
ogist of  Missouri,  noted  the  white  oolite  bed  in  the  vicinity  of  Louisiana, 
Missouri,  and  referred  it  to  the  Onondaga  of  the  Devonian. 

In  the  same  report  Shumard6  described  a  limestone  occurring  near 
Cape  Girardeau,  Missouri,  under  the  name  Cape  Girardeau  limestone, 
and  considered  it  the  oldest  Silurian  formation  in  the  State. 

In  discussing  the  stratigraphic  geology  of  Illinois  in  1866,  Worthen7" 
recognized  the  Girardeau  limestone  in  the  vicinity  of  Thebes,  but  referred 
it  to  the  Ordovician  in  the  upper  part  of  the  Cincinnati  group. 


5Swallow,   G.    C,    Mo.    Geol.    Survey:     Reports    1    and   2,   p.    107,    1855. 
°Shumard,   B.   F.,   Mo.    Geol.    Survey:      Report   2,   p.    154,    1855. 

7Worthen,    A.    H.,    Devonian    and    Silurian    systems   of    Illinois:      Geol.    Survey    of    Illinois, 
vol.   1,  p.    130,   1866. 


70  BIENNIAL   REPORT 

On  a  later  page  of  this  report  Worthen  correlated  with  the  Niagara 
of  northern  Illinois,  the  gray  limestone  forming  the  lower  part  of  the 
Mississippi  River  bluff  in  the  southwest  part  of  Pike  and  the  northwest 
part  of  Calhoun  counties  in  Illinois  (now  known  to  be  of  Sexton  Creek 
or  Brassfield  age). 

On  another  page  he  assigned  to  the  Lower  Helderberg  group  the 
dark  limestone  and  the  overlying  mottled  red  and  gray  limestone  in  the 
vicinity  of  Thebes,  that  represent  respectively  the  Edgewood  and  the  Sex- 
ton Creek  limestone  in  that  portion  of  the  State.     He  says : 

"It  would  appear  probable  that  no  beds  of  undoubted  Niagara  age  were 
ever  laid  down  in  southern  Illinois,  but  in  their  places  these  siliceous  limestones, 
representing  in  part  the  age  of  the  Lower  Helderberg  limestones  and  in  part  the 
Oriskany  sandstones  of  the  New  York  series  were  deposited  resting  directly  upon 
the   Cincinnati  group  of  the   Lower   Silurian." 

In  a  report  on  the  geology  of  Alexander  County,8  Illinois,  published 
in  1868,  the  Girardeau  limestone  is  again  assigned  to  the  Cincinnati  group, 
whereas  the  overlying  gray  limestone,  containing  Dalmanitcs  danai  and 
its  associates,  is  referred  to  the  Lower  Helderberg. 

In  a  paper  presented  to  the  American  Association  for  the  Advance- 
ment of  Science  in  1870,  Worthen9  again  discussed  the  limestones  occur- 
ring between  the  Clear  Creek  (Oriskany)  beds  and  Cape  Girardeau  lime- 
stone in  southwest  Illinois.     He  concluded  that : 

"these  limestones  represent  the  same  geological  horizon  as  the  Niagara  dolomites 
in  the  northern  part  of  the  state;  and  that  the  difference  in  the  specific  character 
of  the  fossils  is  entirely  due  to  the  changes  in  the  oceanic  conditions  under  which 
they  were  deposited,  and  not  to  the  different  ages  of  the   sediments  themselves." 

In  describing  the  geology  of  Calhoun  and  Pike  counties,  Illinois,  in 
1879,  Worthen10  considered  the  gray  limestone  (Sexton  Creek  or  Brass- 
field)  appearing  in  the  lower  part  of  the  Mississippi  River  bluff,  from  near 
the  town  of  Rockport  south  to  Hamburg,  as  the  equivalent  of  the  Niagara 
limestone  in  the  northern  part  of  the  State.  He  regarded  as  the  basal 
member  of  the  Niagara  in  this  region,  the  gray  oolite  and  the  overlying 
buff,  magnesian  limestone,  outcropping  a  few  miles  below  Hamburg,  that 
are  now  known  to  correspond  to  the  Edgewood  as  developed  near  Louis- 
iana, Missouri. 

In  his  description  of  the  geology  of  Will  and  Kankakee  counties,  in 
1870,  WTorthen  did  not  distinguish  the  Alexandrian  series  from  the  Nia- 
gara limestone. 


8Worthen,  A.  H.,  Geology  of  Alexander  County:  Geol.  Survey  of  Illinois,  vol.  3,  pp. 
20-32,   1868. 

9Worthen,   A.   H.,  Am.   Assoc.  Adv.   Sci.,  vol.    19,  p.    172,   1870. 

:"Worthen,  A.  H.,  Geology  of  Calhoun  and  Pike  counties:  Geol.  Survey  of  Illinois,  vol. 
4,  pp.  6,  7,  and  26,  1870. 


ALEXANDRIAN  SERIES  71 

In  a  report  on  the  geology  of  Lincoln  County,  Missouri,  published  in 
1873,  Potter11  referred  the  oolite,  present  in  the  ridges  and  knobs  in  the 
northeast  part  of  this  county,  to  the  Onondaga  of  the  Devonian. 

In  a  paper  intitled,  "A  remarkable  fauna  at  the  base  of  the  Burling- 
ton limestone  in  northern  Missouri,"  in  1892,  Dr.  C.  R.  Keyes12  distin- 
guished the  white  oolite  bed  and  the  overlying  buff  or  brown  limestone 
exposed  near  Louisiana,  and  correlated  them  with  the  Niagara  limestone 
of  Iowa. 

In  describing  the  vertical  range  of  fossils  at  Louisiana,  Missouri,  in 
1897,  Keyes  and  Rowley13  again  referred  the  oolite  bed  and  the  associated 
buff  limestone  in  this  region  to  the  Niagara. 

In  the  following  year  Keyes14  published  a  paper  on  "Some  geological 
formations  of  the  Cap  an  Gres  uplift,"  in  which  the  name  Noix  oolite 
was  proposed  for  the  white  oolite  bed  in  the  vicinity  of  Louisiana,  and  the 
term  Bowling  Green  limestone  was  given  to  the  buff  magnesian  limestone 
near  Bowling  Green,  Missouri.     Of  these  formations  Keyes  writes : 

"The  Noix  oolite  and  the  Bowling  Green  limestone  together  may  be  regarded 
approximately  as  equivalent  to  the  so-called  Niagara  of  the  Upper  Mississippi 
basin." 

In  his  report  on  the  geology  of  Pike  County,  Missouri,  in  1907,  R.  R. 
Rowley15  says : 

"The  Silurian  is  represented  by  a  white  oolitic  and  a  brown  limestone.  The 
oolitic  limestone  attains  a  thickness  of  about  seven  feet,  and  from  its  fauna  is 
thought  to  belong  to  the  Clinton.  The  brown  limestone  overlies  the  white  oolitic 
and  attains  a  maximum  thickness   of  25    feet.     This  horizon   is   clearly  Niagara." 

In  a  paper  by  the  writer16  in  1908,  a  bed  of  cherty  and  mottled  lime- 
stone in  southwestern  Illinois  was  recognized  as  the  equivalent  of  some 
part  of  the  Brassfield  limestone  of  Ohio.  A  distinct  formation  of  early 
Silurian  time  was  also  shown  to  be  present  in  this  region  below  the  Brass- 
held  limestone  and  above  the  Girardeau,  and  separated  from  each  by  a 
sedimentary  break.  The  Silurian  aspect  of  the  fauna  of  the  Girardeau 
limestone  was  emphasized,  and  the  name  Alexandrian  series  was  proposed 
to  embrace  these  post-Cincinnatian  and  pre-Clinton  beds  represented  by 
the  Girardeau  limestone  and  the  succeeding  strata  lying  below  the  equiva- 
lent of  the  Brassfield  limestone. 


"Potter,  W.   B.,  Mo.  Geol.  Survey,  p.  242,  1873. 

12Keyes,  C.  R.,  A  remarkable  fauna  at  the  base  of  the  Burlington  limestone  in  north- 
eastern  Missouri:      Am.  Jour.   Sci.,   3d  series,  vol.  44,  p.  447,   1892. 

13Keyes  and  Rowley,  Vertical  range  of  fossils  at  Louisiana,  Mo. :  Iowa  Acad.  Sci., 
vol.  4,  pp.  26-40,  1897. 

"Keyes,  C.  R.,  Some  geological  formations  of  the  Cap-au-Gres  uplift:  Iowa  Acad.  Sci. 
vol.   5,  pp.  58-63,  1898. 

"Rowley,  R.  R.,  Geology  of  Pike  County:  Mo.  Bur.  Geol.  and  Mines,  vol.  8,  second 
series,  p.   20,   1907. 

1,JSavage,  T.  E.,  Lower  paleozoic  stratigraphy  of  southwestern  Illinois:  Am.  Jour. 
Sci.,  4th  series,  vol.  25,  pp.  431-443,  1908. 


72  BIENNIAL   REPORT 

The  following  year  the  name  Sexton  Creek  limestone  was  defined17 
for  the  Silurian  strata  in  Illinois  that  are  equivalent  to  some  part  of  the 
Brassfield.  The  term  Edgewood  limestone  was  at  the  same  time  applied 
to  that  part  of  the  Alexandrian  series  in  western  Illinois  and  eastern 
Missouri  lying  between  the  Girardeau  and  the  Sexton  Creek  limestones. 

In  discussing  the  faunal  succession  and  the  correlation  of  the  pre- 
Devonian  formations  of  southern  Illinois18  in  1910,  the  significance  of 
the  Silurian  types  of  fossils  in  the  Girardeau  limestone  was  pointed  out ; 
and  the  Channahon  limestone  in  Will  County  was  regarded  as  the  equiva- 
lent of  some  part  of  the  Edgewood  formation  of  southern  Illinois  and 
eastern  Missouri. 

In  a  paper  read  at  the  1911  meeting  of  the  Illinois  Academy  of 
Science,  the  Essex  limestone19  in  Kankakee  County,  was  described  and 
the  formation  was  provisionally  referred  to  the  Alexandrian  series  above 
the  Edgewood  and  below  the  Sexton  Creek  limestone. 

STRATIGRAPHY 
General  Stratigraphic  Relations 

The  strata  comprising  the  Alexandrian  series  in  Illinois  and  Missouri 
are  everywhere  uncomformable  upon  some  horizon  of  the  Richmond,  and 
they  are  separated  by  a  similar  sedimentary  break  from  the  rocks  that  lie 
above  them. 

In  the  south  part  of  the  area,  in  Alexander  and  Union  counties,  Illi- 
nois, and  in  Cape  Girardeau  County,  Missouri,  these  strata  usually  rest 
upon  different  levels  of  the  Orchard  Creek  shale  of  Richmond  age,  and 
are  followed  by  Helderbergian  limestone  having  the  faunal  aspect  of  the 
New  Scotland  of  New  York. 

Farther  north,  in  Jersey,  Calhoun,  and  Pike  counties,  Illinois,  and 
Lincoln,  Pike,  and  Ralls  counties,  Missouri,  the  Alexandrian  overlies  a 
blue  shale  that  in  Illinois  has  been  correlated  with  the  Maquoketa,  and 
in  Missouri  has  been  called  Hudson  River  shale,  and  Buffalo  Creek  shale. 
The  rocks  that  overlie  the  Alexandrian  strata  in  Jersey  County,  Illinois, 
are  of  Niagaran  age,  and  in  the  northern  part  of  Calhoun  County,  Illinois, 
and  across  the  river  in  the  northeast  part  of  Lincoln  County,  Missouri, 
they  are  Devonian  limestones  of  Hamilton  age  belonging  to  the  Iowa  or 
northwest  (Dakota)  province.  A  few  miles  still  farther  north,  in  the 
vicinity  of  Pleasant  Hill,  Illinois,  and  Louisiana,  Missouri,  they  are  im- 
mediately succeeded  by  a  bed  of  dark  shale  of  upper  Devonian  age. 

In  the  northeastern  Illinois  area,  the  Alexandrian  strata  rest  upon 


"Savage,  T.  E.,  Ordovician  and  Silurian  formations  in  Alexander  County,  Illinois:  Am. 
Jour.   Sci.,  4th   series,   vol.   28,   pp.   509-519,   1909. 

18Savage,  T.  E.,  The  faunal  succession  and  the  correlation  of  the  pre-Devonian  forma- 
tions  of   southern    Illinois:      111.    State    Geol.    Survey    Bull.    16,    pp.    302-341,    1910. 

"Savage,  T.  E.,  The  Channahon  and  Essex  limestones  in  Illinois:  Trans.  111.  Acad. 
Sci.,  vol.  4,  pp.   97-103,   1912. 


ALEXANDRIAN  SERIES  73 

the  Maquoketa  shale  and,  where  exposed  beneath  superjacent  strata,  are 
followed  by  dolomites  of  Niagaran  age. 

Thickness  and  Formations  of  the  Series 
The  strata  comprising  the  Alexandrian  series,  as  defined  above,  have 
a  maximum  aggregate  thickness  of  about  175  feet.  The  series  is  divisible 
into  four  formations  which,  with  the  possible  exception  of  the  Essex  lime- 
stone, are  unconformable  among  themselves,  but  their  faunas  are  clearly 
related.  The  sequence  of  the  formations  from  below  upwards  is  as  fol- 
lows :  Girardeau  limestone,  Edgewood  limestone,  Essex  limestone,  and 
Sexton  Creek  (Brassfield)  limestone. 

Girardeau  Limestone 
occurrence  and  stratigraphic  relations 

The  name  Cape  Girardeau  limestone  wras  given  to  the  formation  by 
Shumard  in  1855,  from  Cape  Girardeau,  Missouri,  near  which  town  the 
strata  were  well  exposed.  The  shortened  form  of  the  name  has  been 
adopted  for  this  limestone. 

The  Girardeau  limestone  is  present  only  in  the  south  part  of  the  area 
under  consideration,  and  is  not  known  further  north  than  a  few  miles 
above  Cape  Girardeau,  Missouri.  It  is  well  exposed  in  Illinois  near  the 
mouth  of  Orchard  Creek  about  two  miles  south  of  Thebes,  and  in  the 
bluff  of  Mississippi  River  and  in  some  cuts  along  the  new  Cairo  and 
Thebes  Railroad  for  some  distance  further  south.  It  also  outcrops  in  the 
bank  of  Mississippi  River  and  along  the  Chicago  and  Eastern  Illinois  Rail- 
road one  and  one-half  miles  north  of  Thebes.  In  Missouri  these  strata 
occur  over  a  small  area  in  Cape  Girardeau  County  and  are  exposed  at 
the  type  locality,  about  two  miles  north  of  Cape  Girardeau. 

In  some  places  the  Girardeau  limestone  rests  unconformably  upon 
the  Thebes  sandstone  (Richmond),  and  in  other  places  it  overlies  differ- 
ent horizons  of  Orchard  Creek  shale.  The  rocks  of  this  formation  consist 
of  dark,  fine-grained,  hard,  brittle  limestones  in  layers  two  to  four  inches 
thick.  Thin  lenses  of  hard  calcareous  shale  occur  between  the  layers  of 
limestone ;  both  the  limestone  and  shaly  partings  in  places  contain  numer- 
ous fossils.     The  total  thickness  of  the  formation  is  35  to  40  feet. 

detailed  section 
A  representative  section  of  the  Girardeau  limestone,  exposed  in  the 
east  bank  of  Mississippi  River,  two  and  one-half  miles  south  of  Thebes, 
Illinois,  is  given  below,  beginning  with  ( 1 )  at  the  bottom : 

Section  of  strata  two  and  one-half  miles  south  of  Thebes 
Sexton  Creek   (Brassfield)   limestone — 

5.     Red  or  pink  mottled,  fine-grained,  brittle  limestone,  in  layers   eight  to 
36  inches  thick,  containing  many  small  fossils 8  feet,  10  inches 


74  BIENNIAL  REPORT 

Dalmanella  eleganttila  var.  parva.  Orthoceras  unionensis 

Hebertella  sp.  Illaenus  sp. 

Plectambonites     transversalis     var.     ele-      Phacops  pulchellus 
gantula 

4.     Light  gray,  rather  fine-grained  limestone  with  blotches  of  green  shaly 

material,  containing  many  nodules  of  chert 1  foot,  9  inches 

Favosites  favosus  Plectambonites  transversalis 

Halysites  catenulatus  Stricklandinia  triplesiana 

Zaphrentis  sp.  Triplecia  ortoni  var. 

Clathrodictyon  vesiculosum  Illaenus  cf.  daytonensis 

Orthis  cf.  davidsoni 

3.     Chert  bands,  2  to  4  inches  thick,  separated  by  2  to  3-inch  layers  of  hard, 

impure  limestone  without  fossils 5  feet,  6  inches 

(Break  in  sedimentation) 
Girardeau  limestone — 

2.  Dark   colored,    fine-grained,    hard,   brittle    limestone,   breaking   with   con- 

choidal  fracture,  similar  in  all  respects  to  1 15  feet 

Ptychocrinus  splendens20  Schuchertella  missouriensis 

Tanaocrinus  cf.  typus  Cornulites  tenuistriata 

Archaeocrinus  sp.  Modiolpsis  concinna  n.sp. 

Nematopora  alternata  Conradella  sp. 

Nematopora  delicatula  Diaphorostoma     niagarensis     var.     im- 

Nematopora  fragilis  matura  n.var. 

Nematopora  retrorsa  Acidaspis  halli 

Camarotoechia?  festinata  n.sp.  Calymene  dubia  n.sp. 

Protozeuga  sulcocarinata  n.sp.21  Cyphaspis  girardeauensis 

Rafinesquina?  mesicosta  Proetus  princeps  n.sp. 

Rafinesquina?  delicatula  n.sp. 

1.     Dark-colored,  fine-grained,  hard,  brittle,  limestone  in  layers  2  to  4  inches 
thick,  separated  by  thin  partings  of  calcareous  shale,  and  furnishing 

the  fossils  listed  below 18  feet 

Ptychocrinus  splendens  Rafinesquina?  delicatula  n.sp. 

Tanaocrinus   sp.  Rhynchotrema ?  illinoisensis  n.sp. 

Nematopora  alternata  Schuchertella  missouriensis 

Nematopora  delicatula  Cornulites  incurvus 

Nematopora  fragilis  Cornulites  tenuistriata 

Nematopora  retrorsa  cf.Cyclonema   cancellata 

Camarotoechia?  festinata  n.sp.  Diaphorostoma    niagarensis    var.    imma- 

Dalmanella  modesta  n.sp.  tura  n.var. 

Homoespira  immatura  n.sp.  Pterinea  ornata  n.sp. 

Leptaena  rhomboidalis  Acidaspis  halli 

Lingulops  ovata  n.sp.  Calymene  dubia  n.sp. 

Protozeuga  sulcocarinata  n.sp.  Cyphaspis  girardeauensis 

Rafinesquina?  mesicosta  Encrinurus  deltoideus 


20The  crinoids  collected  from  the  Girardeau  limestone  were  submitted  to  Mr.  Frank 
Springer,  who  made  the  above  identifications.  The  preservation  of  these  was  not  sufficiently 
good  for  illustrations. 

21The  name  Protozeuga  has  been  defined  in  manuscript  by  Dr.  W.  R.  Twenhofel  for 
an  early  Silurian  genus  of  the  brachiopods  having  the  characteristics  of  Woldheima  but  with 
punctate  shells. 


ALEXANDRIAN  SERIES  75 

In  the  foregoing  section,  the  two  lower  members  represent  the  Gir- 
ardeau limestone  in  its  typical  development,  having  at  this  place  a  thick- 
ness of  S3  feet.  The  succeeding  strata,  members  3  to  5  inclusive,  belong 
to  the  Sexton  Creek  (Brassfield)  limestone,  the  two  formations  being 
separated  by  a  sedimentary  hiatus.  The  Edgewood  strata  which,  north 
of  Thebes,  appear  below  the  Sexton  Creek  limestone,  are  not  present  in 
this  locality. 

The  decidedly  Silurian  aspect  of  the  fauna  of  the  Girardeau  lime- 
stone appears  in  the  lists  presented  above.  The  post-Richmond  age  of 
the  Girardeau  limestone  is  shown  by  the  total  absence  of  a  single  char- 
acteristic Richmond  species  in  the  formation,  and  also  by  the  presence 
of  such  Silurian  genera  as  Schuchcrtclla,  Homoeospira,  Camarotoechia? 
Diaphorostoma,  Protozcuga,  and  Proetus.  The  only  species  in  the  Gir- 
ardeau fauna  that  are  listed  by  Cumings  from  the  Richmond  strata  of 
Indiana,  or  that  are  known  to  occur  in  the  Maquoketa  (Richmond) 
strata  of  Iowa  and  Illinois,  are  Lcptaena  rhomboidalis  and  Cornulites 
tciiuistriata,  neither  of  which  possesses  any  stratigraphic  significance. 

It  should  be  noted  also  that  the  most  abundant  and  characteristic  of 
the  Girardeau  species,  as  Schuchertclla  missouricnsis,  Rafinesquinaf 
mesicosta  and  Protozeuga  side  o  car  mat  a,  continue  upward  into  the  suc- 
ceeding Edgewood  limestone.  Regardless  of  whether  the  Richmond  shall 
eventually  be  transferred  from  its  present  position  in  the  Ordovician 
(where  in  the  mind  of  the  writer  it  should  remain)  to  the  Silurian  system, 
the  Girardeau  limestone  appears  positively  of  post-Richmond  age,  and 
clearly  represents  the  earliest  deposits  of  the  early  Silurian  sea  that  ad- 
vanced into  this  region  from  the  south  during  this  epoch  of  submergence 
which  culminated  in  the  Brassfield  transgression. 

Edgewood  Limestone 
occurrence  and  stratigraphic  relations 

The  name  Edgewood  limestone  was  proposed  in  190922  for  the  strata 
occurring  between  the  Girardeau  limestone  and  the  Sexton  Creek  (Brass- 
field)  limestone  in  southwest  Illinois  and  eastern  Missouri. 

In  1898,  C.  R.  Keyes23  proposed  the  name  Noix  oolite  for  the  white 
oolite  bed  outcropping  along  Noix  Creek  at  Louisiana,  Missouri ;  and 
the  name  Bowling  Green  limestone  for  the  brown  magnesian  limestone 
that  is  well  exposed  a  few  miles  farther  west,  in  the  vicinity  of  Bowling 
Green. 


—Savage,  T.  E.,  Ordovician  and  Silurian  formations  in  Alexander  County,  Illinois :  Am. 
Jour.  Sci.,  vol.  28,  p.   517,  1909. 

23Keyes,  C.  R.,  Vertical  range  of  fossils  at  Louisiana,  Missouri :  Proc.  Iowa  Acad.  Sci., 
vol.  4,  p.  27,   1897. 


76  ,  BIENNIAL  REPORT 

Where  the  oolite  is  best  developed,  as  at  Louisiana,  its  fossils  indicate 
that  this  bed  is  the  equivalent  of  about  the  upper  two-thirds  of  the  Edge- 
wood  limestone,  as  exposed  in  the  vicinity  of  Thebes,  Illinois,  and  of  the 
corresponding  part  of  the  limestone  present  near  the  town  of  Edgewood, 
Missouri.  It  represents  a  local,  shallow  water  phase  of  sedimentation  in 
this  region  during  only  a  part  of  Edgewood  time.  This  was  recognized 
by  Keyes  in  the  following  statement : 

"The  oolite  (Noix)  appears  to  be  somewhat  of  a  local  phase,  but  is  present 
not  only  in  the  vicinity  of  Louisiana,  but  all  the  way  to  Paynesville,  a  distance 
of  18  miles.  The  formation  appears  to  be  represented  elsewhere  in  the  vicinity 
by  fossiliferous  limestones  that  are  not  oolitic." 

The  strata  to  which  the  name  Bowling  Green  limestone  was  applied, 
consist  of  about  thirty  feet  of  brown  somewhat  massive  limestone,  the 
middle  and  upper  parts  of  which  contain  few  or  no  fossils,  but  the  lower 
one  or  two  feet  carries  a  fauna  similar  to  that  found  in  the  oolite  at  Louis- 
iana, and  in  the  upper  part  of  the  fossiliferous  portion  of  the  Edgewood 
limestone  in  the  vicinity  of  Edgewood,  Missouri. 

Inasmuch  as  the  succession  of  strata  from  the  base  of  the  Edgewood 
to  the  top  of  the  Bowling  Green  limestone  appears  to  be  unbroken,  it  is 
desirable  to  include  all  of  these  strata  under  a  single  formation  name. 
For  this  more  comprehensive  series  of  deposits  the  term  Noix  oolite  is 
not  appropriate,  because  the  oolite  phase  is  developed  only  over  a  small 
part  of  the  area  of  distribution  of  these  strata,  nor  does  it  anywhere  in- 
clude the  entire  thickness.  Neither  is  the  name  Bowling  Green  limestone 
desirable,  for  it  was  proposed  for  the  limestone  near  Bowling  Green,  Mis- 
souri, which  represents  only  the  upper  and  mostly  unfossiliferous  portion 
of  the  Edgewood.  On  the  other  hand,  the  name  Edgewood,  as  originally 
proposed,  embraces  all  of  the  strata  between  the  Girardeau  limestone  and 
the  Sexton  Creek  (Brassfield)  limestone  in  this  region.  The  lower  fossil- 
iferous portion  of  the  formation  and  the  overlying  brown,  unfossiliferous 
Bowling  Green  phase  are  both  well  developed  in  the  vicinity  of  Edgewood, 
Missouri,  whereas  the  lowest  beds  of  the  Edgewood  are  not  known  north 
of  this  locality. 

For  these  reasons  the  name  Edgewood  limestone  is  retained  as  the 
formation  name  that  includes  all  the  strata  in  Missouri  and  Illinois,  be- 
tween the  horizon  of  the  Girardeau  limestone  and  the  top  of  the  magnesian 
limestone  near  Bowling  Green,  and  the  top  of  the  brown  limestone  over- 
lying the  oolite  in  Lincoln,  Pike,  and  Ralls  counties,  Missouri,  and  on  the 
opposite  side  of  the  river  in  Illinois,  and  their  equivalents  elsewhere  in 
the  Mississippi  valley. 

It  will  be  convenient,  however,  to  subdivide  the  Edgewood  forma- 
tion into  three  members,  as  follows:      (1)   The  Cyrene  member,  which 


ALEXANDRIAN  SERIES  77 

will  include  the  lower,  fossiliferous  limestone  phase  of  the  formation, 
below  the  Bowling  Green  member,  exposed  one  to  two  miles  east  of 
Cyrene  and  Edgewood  in  Pike  County,  Missouri,  and  about  two  miles 
north  of  Thebes  in  Alexander  County,  Illinois;  (2)  The  Noix  oolite 
member  which  will  refer  to  the  local  oolite  facies  of  the  formation,  which 
is  the  equivalent  of  a  variable  portion  of  the  upper  part  of  the  Cyrene 
member;  and  (3)  the  Bowling  Green  member,  which  will  embrace  the 
buff  or  brown  mostly  nonfossiliferous  limestone  in  the  upper  part  of  the 
formation,  corresponding  to  the  strata  outcropping  near  Bowling  Green, 
Missouri. 

The  name  Channahon  limestone  will  be  retained  for  easy  reference 
to  the  strata  seen  only  along  Desplaines  River  one  mile  southeast  of  Chan- 
nahon in  Will  County,  Illinois.  This  limestone  is  considered  the  equiva- 
lent of  some  part  of  the  Edgewood  formation,  but  it  cannot  yet  be  cor- 
related with  any  particular  part  of  it  because  of  the  complete  isolation 
of  the  area  from  other  exposures  of  the  Edgewood  limestone,  and  the 
slight  difference  in  its  fauna  from  that  of  the  typical  Edgewood  limestone 
in  eastern  Missouri  and  southwest  Illinois. 

Strata  representing  parts  of  the  Edgewood  limestone  are  nearly  coex- 
tensive with  the  distribution  of  the  Alexandrian  series  in  the  states  of 
Illinois  and  Missouri.  The  lower,  fossiliferous  layers  of  the  formation 
(Cyrene  member)  are  present  near  the  river  in  Alexander  County,  Illi- 
nois ;  and  over  a  considerable  area  in  the  vicinity  of  Edgewood  and 
Cyrene,  in  Pike  County,  Missouri,  where  they  are  in  places  overlain  by 
the  Bowling  Green  member.  Farther  north,  near  Bowling  Green  and 
McCune  Station,  the  Cyrene  member  of  the  Edgewood  is  mostlv  absent, 
and  the  overlying  Bowling  Green  member  makes  up  the  greater  part  of 
the  formation. 

DETAILED    SECTIONS 

An  excellent  exposure  of  the  lower  strata  of  the  Edgewood  limestone 
appears  in  Illinois  along  the  east  bank  of  the  Mississippi  River,  about  one 
and  one-half  miles  north  of  Thebes,  where  they  occur  in  the  bottom  of  a 
low  syncline,  and  occupy  an  old  channel  eroded  in  the  Girardeau  lime- 
stone during  the  post-Girardeau  pre-Edgewood  land  interval.  The  suc- 
cession of  strata  at  this  place  is  shown  in  the  following  detailed  section : 


78  BIENNIAL  REPORT 

Section  exposed  along  the  river  one  and  one-half  miles  north  of  Thebes 
Edgewood  formation    (Cyrene  member)  — 

10.     Heavy    layer    of    gray,    coarsely    granular    limestone,    oolitic    in    the 

upper  part,  containing  many  fossils 3  feet,  6  inches 

Clathrodictyon  vesiculosum  Schuchertella  propinqua 

Lyellia  thebesensis  Spirifer  (Delthyris)   sp. 

Zaphrentis    stokesi  Whitfieldella  billingsana 

Atrypa  putilla  Pterina  thebesensis 

Atrypa  tubulistriata  n.sp.  Lophospira  thebesensis  n.sp. 

Clorinda?  thebesensis,  n.sp.  Cyphaspis  intermedia 

Leptaena  rhomboidalis  Metapolichas  breviceps  var.  clintonensis 

Rhynchotreta   thebesensis  Proetus  determinatus 

9.     Rather  soft,  gray  shale,  without  fossils 1  foot,  2  inches 

8.  Dark-gray,  argillaceous  limestone  or  calcareous  shale,  in  two  layers, 
each  about  six  inches  thick,  separated  by  a  two-inch  parting  of 
softer    shale.     The    calcareous    layers    contain    the    fossils    listed 

below 1   foot,  6  inches 

Clorinda?   thebesensis  n.sp.  Whitfieldella  ovoides  n.sp. 

Rafinesquina?   mesicosta  Bellerophon  consimilis  n.sp. 

Schuchertella  propinqua  Dalmanites  danai 

7.     Rather  soft,  gray  shale,  without  fossils 1  foot,  6  inches 

6.  Layer  of  somewhat  fissile,  fine-grained,  argillaceous  limestone,  con- 
taining   few    fossils 1  foot,  6  inches 

5.     Layer  of  rather  hard  limestone,  having  a  2-inch  band  of  chert  at  the 

top  ;  no  fossils  found 8  inches 

4.  Layer  of  conglomerate  consisting  of  fragments  of  Girardeau  lime- 
stone, from  2  to  12  inches  in  diameter,  imbedded  in  a  matrix  of 
fine-grained  limestone.  In  some  places  this  member  appears  to  be 
composed  of  calcareous  concretions  surrounded  by  softer,  bluish- 
gray   shale 2  feet,  6  inches 

(A   break  in    deposition) 
Girardeau  limestone — 

3.  Hard,  fine-grained,  brittle,  dark-colored  limestone,  with  fossils  char- 
acteristic of  the  Girardeau  formation 2  feet,  6  inches 

(A  possible  break  in  deposition) 
Orchard  Creek  shale — 

2.     Bluish-gray,    calcareous    shale,    containing    one    to    2-inch    bands    of 

shaly,  concretionary  limestone,  4  to  6  inches  apart 18  feet 

(A  break  in    deposition) 
Thebes  sandstone — 

1.  Brown-  or  chocolate-colored,  rather  fine-grained  sandstone,  which 
weathers  into  thin  layers 40  feet 

In  the  above  section,  the  members  4  to  10  inclusive,  constitute  the 
Edgewood  beds,  as  that  formation  is  seen  at  its  best  exposure  in  south- 


ALEXANDRIAN  SERIES  79 

west  Illinois.  At  this  place  the  Girardeau  limestone  was  almost  entirely 
cut  out  by  erosion  prior  to  the  deposition  of  the  Edgewood  strata.  A 
thickness  of  13  or  more  feet  of  the  Girardeau  limestone  outcrops  in  the 
river  bluff  a  few  rods  north  of  the  place  where  the  section  was  made. 
The  conglomerate  at  the  base  of  the  Edgewood,  number  4  in  the  section, 
is  composed  largely  of  fragments  of  Girardeau  limestone. 

Another  instructive  exposure  of  the  Edgewood  strata  in  this  vicinity 
is  in  an  abandoned  quarry  one-fourth  mile  southeast  of  the  village  of 
Gale,  about  two  miles  northeast  of  Thebes.  This  is  in  the  northeast  quar- 
ter of  sec.  4.  T.  15  S.,  R.  3  W.,  where  the  following  section  was  made: 

Section  in  abandoned  quarry  one-fourth  mile  southeast  of  Gale 

4.     Sexton  Creek   (Brassfield)    limestone- 
Hard,  gray  limestone,   in  layers  4  to  8  inches  thick,   which  are 
separated  one  from  another  by  2  to  3-inch  chert  bands.  .11  feet 
(A  break  in  sedimentation) 

3.     Edgewood   formation    (Cyrene   member)  — 

Single  layer  of  gray,  somewhat  oolitic  limestone,  containing 
small  pebbles  of  chert,  one-fourth  inch  to  4  inches  in  di- 
ameter   10    inches 

Calvinia  edgewoodensis  n.gen.,  n.sp.  Dalmanella  edgewoodensis  n.sp. 

Lyellia  thebesensis  Hindella?    ambigua    n.sp. 

Zaphrentis  stokesi  Rhynchonella?  janea 

Atrypa  praemarginalis,  n.sp.  Rhynchotreta  parva  n.sp. 

Atrypa  putilla  Cyclonema  daytonensis 

Camarotoechia?  antiqua  n.sp.  Lophospira  fasciata  n.sp. 

Camarotoechia?  concinna  n.sp.  Metapolichas  breviceps  var.  clintonensis 

(A  break  in  sedimentation) 

2.  .  Orchard  Creek  shale — 

Bluish-gray  calcareous  shale,  bearing  1  to  2-inch  bands  of  impure, 

concretionary  limestone,  4  to  6  inches  apart 8  feet 

(A  break  in  sedimentation) 
1.     Thebes   sandstone — 

Brown,  fine-grained,  slightly  shaly  sandstone,  at  the  top  of  which 
is  a  hard,  deeply  iron-stained  zone 6  feet 

In  the  section  given  above,  the  single  layer  comprising  the  third 
member,  represents  the  total  thickness  of  the  Edgewood  formation  at 
this  place.  It  belongs  probably  to  a  level  a  little  higher  than  that  of  the 
uppermost  layer  in  the  preceding  section. 

Strata  equivalent  to  those  of  the  Edgewood  limestone  near  Thebes, 
Illinois,  are  well  developed  in  the  vicinity  of  Edgewood,  in  Pike  County, 
Missouri.  Along  the  streams  one  to  one  and  one-half  miles  east  and 
northeast  of  this  town  the  following  strata  are  exposed: 


80  BIENNIAL  REPORT 

Section  of  strata  one  and  one-half  miles  northeast  of  Edgezvood,  Missouri 

Thickness 
Edgewood  limestone —  Feet 

3.     Brown  to  yellow  limestone,  with   few  or  no   fossils    (Bowling 

Green  limestone  member) 22 

2.     Brown   limestone,   in   layers   two   to    six   inches   thick,    with   Schuch- 
ertella  propinqua   and   Dalmanites   danai,   common   in   the 
lower    part,    and    Atrypa    praemarginalis,    A.    put  ilia    and 
Dalmanella  edgeivoodensis  abundant  in  the  upper;  contain- 
ing the  greater  number  of  the  fossils  indicated  in  column  2 

of  the  following  table   (Cyrene  member) 6-11 

(A  break  in  sedimentation) 
Maquoketa   (Richmond)   shale — 

1.     Bluish-gray  shale,  with  Strophomena  rugosa,  Isotelus  sp.,  and 

other  fossils    9-14 

In  a  few  places  in  this  vicinity,  the  limestone  corresponding  to  the 
Cyrene  member  is  light  gray,  but  in  most  places  its  color  is  brown.  The 
upper  1  or  2  feet  of  this  limestone,  immediately  below  the  Bowling  Green 
member,  contains  a  somewhat  different  fauna  in  different  localities. 

In  some  places,  as  southeast  of  Edgewood,  south  of  Clarksville,  and 
at  Louisiana,  the  upper  layer  contains  many  corals,  including  Calapoecia 
favositoidca,  Clathrodictyon  vcsiculosum,  Favosites  subelongus,  Lyellia 
thebesensis,  Zaphrentis  subregularis,  the  form  of  Platystrophia  described 
by  Foerste,  as  P.  daytonensis,  Whitfieldella  ovoides  and  Cyclonema  day- 
tonensis. In  other  places  the  corals  are  mostly  absent  from  this  layer 
and  its  fauna  consists  largely  of  species  of  Atrypa,  Camarotoechia?  and 
Dalmanella. 

A  few  miles  north  of  Edgewood,  between  Bowling  Green  and  Wat- 
son Station,  and  still  farther  north  in  the  vicinity  of  McCune  Station,  the 
Edgewood  limestone  is  represented  by  25  to  35  feet  of  brown,  nonfossil- 
iferous  limestone  (Bowling  Green  member)  at  the  base  of  which  is  in 
places  a  band  one  and  one-half  to  two  feet  thick,  containing  numerous 
shells  of  Atrypa  praemarginalis,  A.  putilla,  Camarotoechia?  concinna  and 
Dalmanella  edgeivoodensis.  This  lower  fossiliferous  band  corresponds 
to  only  the  upper  part  of  the  Cyrene  member  in  the  section  northeast  of 
Edgewood. 

Deposition  of  the  Bowling  Green  limestone  member  is  thought  to 
have  been  initiated  by  a  slight  uplift  of  the  region  bordering  the  west 
side  of  this  basin  in  Lincoln,  Pike,  and  Ralls  counties,  Missouri,  accom- 
panied by  a  slight  subsidence  of  the  area  east  of  the  line  of  uplift,  but 
sedimentation  appears  generally  to  have  been  uninterrupted  from  the  top 


ALEXANDRIAN  SERIES  81 

of  the  fossiliferous  part  of  the  Edgewood  into  the  Bowling  Green  mem- 
ber. This  movement  put  a  stop  to  oolite  deposition  and  so  quickened 
erosion  of  the  land  on  the  west  as  to  increase  the  discharge  of  mechanical 
sediments  into  the  basin. 

From  3  to  6  miles  west  of  Mississippi  River  the  limestone  equivalent 
to  the  upper  layers  of  the  Cyrene  member  near  Edgewood,  passes  with 
a  gradual  transition  into  a  thin  bed  of  gray  oolite  which  thickens  towards 
the  east,  attaining  its  maximum  in  the  vicinity  of  Louisiana,  Missouri.  A 
variable  thickness  of  brown  Bowling  Green  limestone  usually  overlies  the 
oolite,  being  thickest  where  the  oolite  is  thinnest,  and  thinnest  where  the 
oolite  is  best  developed.  However,  the  oolite  bed  does  not  increase  in 
thickness  at  the  expense  of  the  lower  part  of  the  Bowling  Green  lime- 
stone, but  where  the  oolite  is  thickest  there  is  represented  a  greater  thick- 
ness of  the  upper  part  of  the  Cyrene  limestone  member. 

There  is  given  below  a  section  of  the  strata  exposed  in  the  south 
bank  of  Noix  Creek,  at  Louisiana,  Missouri,  where  the  oolite  bed  has 
its  greatest  known  development. 

Section  along  Noix  Creek,  at  Louisiana,  Missouri 

Thickness 
3.     Upper  Devonian  shale —  Feet 

Dark  colored,  fissile  shale,  with  few  fossils 3 

(A  break  in  sedimentation) 

2.     Edgewood   limestone    (Noix  oolite)  — 

Light  gray  oolite,  in  three  layers,  containing  the  greater 
number  of  the  fossils  indicated  in  column  3  of  the  follow- 
ing table    8 

(A  break  in  sedimentation) 

1.     Maquoketa    (Richmond)    shale — 

Bluish  to  greenish-gray  shale,  with  few  or  no   fossils....  9 

The  Bowling  Green  limestone  is  absent  at  the  place  where  the  above 
section  was  made,  but  2  to  4  feet  of  this  limestone  is  present  above  the 
oolite  less  than  one  mile  west ;  and  6  to  8  feet  of  the  Bowling  Green  lime- 
stone overlies  the  oolite  at  the  mouth  of  Buffalo  Creek,  one  and  one-hali 
miles  southeast  of  Louisiana. 

As  is  common  with  oolite  faunas  most  of  the  shells  in  the  oolite  at 
Louisiana  are  distinctly  smaller  than  those  of  corresponding  species  from 
the  limestone  that  is  not  oolitic.  They  are  often  so  silicified  that  peifect 
specimens  of  even  the  smallest  forms  can  be  obtained  by  dissolving  the 
limestone  with  weak  acid.  The  fossils  from  the  oolite  at  Louisiana  are 
indicated  by  a  cross  to  the  right  of  the  name,  in  the  third  column  of  the 
table  given  below.     A  cross  opposite  the  name,  in  the  second  column  of 


82 


BIENNIAL  REPORT 


the  table  shows  that  the  species  was  found  in  the  Edgewood  limestone, 
near  Edgewood,  Missouri ;  and  a  cross  opposite  the  name  in  the  first 
column  indicates  the  presence  of  that  species  in  the  Edgewood  limestone 
near  Thebes,  Illinois. 

Comparative  table  of  fossils  from  the  Edgewood  formation,  near  Thebes,  Illinois; 
near  Edgewood,  Missouri;  and  the  Noix  oolite,  near  Louisiana,  Missouri 


FOSSILS 


^•2  3 

2  »?  o 


Calapoecia    f avositoidea   n.sp 

Calvinia  edgewoodensis  n.gen.,  n.sp 

Clathrodictyon  vesiculosum  Nicholson  and  Murie 

Favosites  subelongns  n.sp 

Halysites  catenulatus  Linnaeus 

Lyellia  thebesensis  Foerste 

Zaphrentis  cf.  ambigtia  n.sp 

Zaphrentis   subregularis   n.sp 

Zaphrentis  cf.  stokesi  Edwards  and  Haime 

Atrypa  praemarginalis  n.sp 

Atrypa  putilla   (Hall  and  Clarke) 

Atrypa  tubulistriata  n.sp 

Brachyprion   stropheodontoides  n.sp 

Brachyprion  latisculptilis  n.sp 

Camarotoechia  ?  antiqua  n.sp 

Camarotoechia  ?    concinna   n.sp 

Clorinda  ?  thebesensis  n.sp 

Dalmanella  edgewoodensis,  n.sp 

Hindella  ?  ambigua  n.sp 

Homoeospira  fiscellostriata  n.sp 

Homoeospira    subcircularis    n.sp 

Leptaena  rhomboidalis   (Wilckens) 

Orthis  flabellites  var.  fissiplicata  Foerste 

Pentamerus  parvulus  n.sp 

Platystrophia  daytonensis  Foerste 

Protozeuga  sulcocarinata  n.sp 

Rafinesquina?   mesicosta    (Shumard) 

Rafinesquina?  mesicosta  var.  mesistria  n.var 

Rhipidomella   tenuilineata   n.sp 

Rhynchonella  ?   janea   Billings 

Rhynchotreta  parva  n.sp 

Rhynchotreta   thebesensis   Foerste 

Rhynchotreta  thebesensis  var.  multistriata  n.var.., 

Schuchertella  cf.  missouriensis   (Shumard) 

Schuchertella  missouriensis  var.  convexa  n.var.., 


X 


X 


X 


ALEXANDRIAN  SERIES 


83 


Comparative  table  of  fossils  from  the  Edgewood  formation,  near  Thebes,  Illinois 

near  Edgewood,  Missouri;  and  the  Noix  oolite,  near  Louisiana, 

Missouri — Concluded 


FOSSILS 


o 
be  3 

y,  o 


3.2  3 

O   <r<   O 

u   3   x 


Schuchertella  propinqua   (Meek  and  Worthen)  . .  . 

Spirifer    (Delthyris)    sp 

Whitfieldella  billingsana   (Meek  and  Worthen)... 

Whitfieldella  ovoides  n.sp 

Whitfieldella   speciosa  n.sp 

Bellerophon   consimilis   n.sp 

Bellerophon  cf.  exiguus  Foerste 

Bucania   sp 

Cyclonema   daytonensis   Foerste 

Diaphorostoma  niagarensis    (Hall) 

Holopea   mintita   n.sp 

Hormotoma  tenera  n.sp 

Liospira  cf.  afnne   (Foerste) 

Lophospira  f asciata  n.sp 

Lophospira  thebesensis  n.sp 

Poleumita  bellasculptilis  n.sp 

Straparollus   pumilis    n.sp 

Colpomya   abrupta   n.sp 

Ctenodonta  subelliptica  n.sp 

Cypricardinia  subquadrata  n.sp 

Pterinea  thebesensis  Meek  and  Worthen 

Dawsonoceras  cf.  tenuilineatum  n.sp 

Cyphaspis  intermedia  Weller 

Dalmanites  danai  Meek  and  Worthen 

Isotelus  longaevus  n.sp 

Metapolichas  breviceps  var.  clintonensis   (Foerste) 
Proetus  determinatus  Foerste 


X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

x 

X 

X 

X 

X 

X 

x 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

.. 

X 

X 

X 

X 

X 

X 

X 

X 

x 

X 

X 


The  close  similarity  of  the  fossils  from  the  different  Edgewood  local- 
ities compared  in  the  above  table,  leaves  no  doubt  of  the  general  equiva- 
lence of  the  strata  from  which  they  came.  The  oolite  bed  at  Louisiana 
(Xoix  oolite  member)  is  equivalent  to  about  the  upper  one-half  or  two- 
thirds  of  the  Cyrene  member  of  the  Edgewood  limestone  as  developed 
near  Thebes,  Illinois,  and  east  of  Edgewood,  Missouri. 

East  of  Louisiana,  the  oolite  bed  becomes  thinner  so  that  where  it 
appears  in  the  Mississippi  bluff  on  the  Illinois  side  of  the  river,  10  miles 
east  of  Louisiana,  a  thickness  of  about  three  feet  is  present.  In  these 
more  easterly  exposures  of  the  bed,  in  Pike  and  Calhoun  counties,  Illinois, 
the  lower  part  of  the  oolite  present  at  Louisiana,  Missouri,  is  absent,  and 


S4  BIENNIAL  REPORT 

the  bed  is  overlain  by  12  to  16  feet  of  brown  Bowling  Green  limestone, 
which  is,  in  turn,  followed  by  the  Sexton  Creek  (Brassfield)  limestone. 

Near  the  south  margin  of  the  area  of  outcrop  of  the  Alexandrian 
strata  in  northeast  Illinois,  in  the  east  bank  of  Kankakee  River,  three  and 
one-half  miles  above  Custer  Park,  there  is  exposed  a  bed  of  iron-stained 
oolite,  three  and  one-half  feet  thick,  which  is  thought  to  be  the  equivalent 
of  the  Noix  oolite  in  Missouri  and  western  Illinois.  It  rests  upon  Ma- 
quoketa  shale  and  is  succeeded  by  6  to  9  feet  of  brown  limestone,  resemb- 
ling the  Bowling  Green  member,  which  is,  in  turn,  followed  by  the  Sex- 
ton Creek  (Brassfield)  limestone. 

The  oolite  development  appears  to  be  restricted  to  the  north  and 
east  parts  of  the  area  of  the  Edgewood  limestone,  bordering  Mississippi 
River,  and  to  the  south  side  of  the  area  of  Alexandrian  rocks  in  north- 
eastern Illinois. 

CHANNAHON    LIMESTONE    MEMBER 

In  the  northeast  Illinois  area,  the  Channahon  limestone  member  of 
the  Edgewood  limestone,  is  exposed  along  the  south  bank  of  Desplaines 
River,  about  one  mile  southeast  of  the  village  of  Channahon,  in  Will 
County.  This  limestone  also  underlies  the  surficial  materials  over  a 
limited  area  on  the  north  side  of  the  river.  A  section  of  strata  exposed 
at  the  former  locality  is  as  follows : 

Section  of  Channahon  limestone,  near  Channahon,  Illinois 

Thickness 
Ft.  In. 
3.     Dark  gray  to  brown,  rather  fine-grained,  impure  limestone  in 

layers  3  to  6  inches  thick,  containing  many  fossils 1         6 

2.  Dark  colored  limestone,  consisting  of  a  fine-grained  matrix  in 
which  are  imbedded  numerous  simple  corals,  besides  Lep- 
taena    rhomb oidalis,    Schnchertella    curvistriata,    Pterinea 

clegans,  Mctapolichas  ferrisi  and  other  fossils 2        6 

1.     Fine-grained,    yellowish-gray,    laminated    sandstone,    without 

fossils,  to  the  level  of  the  water  in  the  river 5 

In  the  above  section  there  is  no  apparent  unconformity  between  the 
different  members,  although  the  lithology  of  the  sandstone  at  the  base  is 
markedly  different  from  that  of  the  overlying  limestone,  and  the  numerous 
corals  occurring  in  the  second  member  are  absent  from  the  upper  bed. 
The  contact  of  these  rocks  with  the  Maquoketa  shale  below,  or  with 
Silurian  limestone  above,  cannot  be  seen  at  the  place  where  the  section  was 
made.  However,  early  Silurian  strata  thought  to  represent  some  part  of 
the  Sexton  Creek  (Brassfield)  limestone,  are  exposed  a  few  rods  east 
of  this  place  at  a  level  only  a  few  feet  higher  than  the  top  of  the  upper- 
most member  of  the  section.     A  blue  plastic  shale,  that  doubtless  belongs 


ALEXANDRIAN  SERIES 


85 


to  the  Maquoketa,  outcrops  in  the  bank  of  the  river  about  one-half  mile 
further  east  at  an  altitude  slightly  above  that  of  the  top  of  the  section.  In 
the  vicinity  of  Millsdale  where  the  contact  of  the  lower  layers  of  Silurian 
limestone  with  the  underlying  Maquoketa  shale  is  well  exposed,  the 
Channahon  limestone  is  absent. 

The  Channahon  limestone  furnished  the  fossils  listed  in  the  left 
hand  column  below.  In  the  column  on  the  right  are  given  the  names  of 
the  species  from  the  Edgewood  limestone  in  Missouri  and  Alexander 
County,  Illinois,  that  are  nearly  related  to  the  respective  Channahon  forms. 

Comparative  table  of  fossils 
Fossils   from   the    Channahon   limestoneFossils    from   the    Edgewood    formation 


in  Will  County,  Illinois — 

Zaphrentis  ambigua  n.sp. 
Zaphrentis  subregularis  n.sp. 
Zaphrentis     stokesi     Edwards     and 

Haime? 
Atrypa  sp. 

Dalmanella  cf.  edgewoodensis  n.sp. 
Leptaena  rhomboidalis  (Wilckens) 
Lingulops  illinoisensis  n.sp. 
Pholidops  subelliptica  n.sp. 
Rhipidomella  hybrida  (Sowerby) 
Rhynchotreta  lepida  n.sp. 
Rhynchotreta  intermedia  n.sp. 
Schuchertella  curvistriata  n.sp. 

Whitfieldella  acuminata  n.sp. 

Whitfieldella  ovoides  n.sp. 
Callonema  pristina  n.  sp. 
Cyclonema  daytonensis  Foerste. 
Diaphorostoma  illinoisensis  n.sp. 
Pterinea  elegans  n.sp. 
Dawsonoceras  tenuilineatum  n.sp. 

Cyphaspis  intermedia  Weller 
Metapolichas   ferrisi  Weller 


in  Missouri,  and  Alexander  County, 
Illinois — 

Zaphrentis  ambigua  n.sp. 

Zaphrentis  subregularis  n.sp. 

Zaphrentis  stokesi  Edwards  and 
Haime 

Atrypa  putilla  (Hall  and  Clarke) 

Dalmanella  edgewoodensis  n.sp. 

Leptaena  rhomboidalis   (Wilckens) 


Rhynchotreta  parva  n.sp. 
Rhynchotreta  thebesensis  Foerste 
Schuchertella    propinqua     (M.    and 

W.) 
Whitfieldella    billingsana    (M.    and 

W.) 
Whitfieldella  ovoides  n.sp. 

Cyclonema  daytonensis  Foerste 
Diaphorostoma  niagarensis  (Hall) 
Pterinea  thebesensis  M.  and  W. 
Dawsonoceras      cf.      tenuilineatum 

n.sp. 
Cyphaspis  intermedia  Weller 
Metapolichas  breviceps  var.  clinton- 

ensis    (Foerste) 
Proetus  determinatus  Foerste 


Proetus  channahonensis  Weller 
Leperditia  illinoisensis  n.sp. 

Whereas  the  correspondence  of  the  respective  species  of  fossils  com- 
pared from  the  two  areas  is  not  identical,  yet  the  differences  between 
many  of  them  are  slight.  The  fauna  of  the  Channahon  limestone  is  more 
closely  related  to  that  of  the  Edgewood  formation  than  to  any  other  known 
fauna. 


86  BIENNIAL  REPORT 

It  is  thought  that  the  strata  in  the  two  areas  represent  about  the  same 
period  of  deposition ;  and  that  the  differences  in  the  fossils  are  due  largely 
to  differences  in  the  marine  environments  of  the  faunas  in  the  respective 
regions. 

Essex  Limestone 
occurrence  and  stratigraphic  relations 

The  Essex  limestone  includes  the  strata  outcropping  along  Horse 
Creek,  one  and  one-half  miles  east  of  the  town  of  Essex,  in  Kankakee 
County,  Illinois.  It  occupies  a  position  in  the  upper  part,  or  above  the 
Edgewood  limestone,  and  below  the  Sexton  Creek  (Brassfield)  limestone. 

DETAILED    SECTION 

The  character  of  the  Essex  limestone  is  shown  in  the  following  de- 
tailed section : 

Section  of  Essex  limestone  near  Essex,  Illinois 

Thickness 
Ft.  In. 
Sexton  Creek  (Brassfield)   limestone — 

3.     Yellowish-brown,  much  weathered  masses  of  magnesian  lime- 
stone,   containing   nodules   and   masses   of    chert,    bearing 

pentamerella?  manniensis  and  other  fossils 3        6 

Essex  limestone — 

2.     Yellowish-brown,  thin-bedded,  magnesian  limestone,  in  layers 

3  to  5  inches  thick,  with  numerous  fossils 8        6 

1.     Rather  hard,  bluish-colored,  shaly  limestone,  in  layers  2  to  6 

inches  thick,  exposed  above  the  level  of  low  water 2        - 

The  contact  between  the  members  2  and  3  in  the  above  section  is  not 
so  clearly  exposed  that  the  presence  or  absence  of  a  depositional  hiatus 
between  them  could  be  certainly  determined.  Farther  south,  in  Pike 
County,  Missouri,  and  Calhoun  County,  Illinois,  Pentamerella?  man- 
niensis is  a  guide  to  the  basal  layers  of  the  Sexton  Creek  (Brassfield) 
limestone.  Hence,  the  upper  limestone,  number  3  of  the  section,  is  re- 
ferred to  the  Sexton  Creek  formation.  The  fauna  of  the  Essex  limestone, 
numbers  1  and  2  of  the  section,  has  not  been  recognized  farther  south  in 
Illinois  and  Missouri.  It  may  be  found  to  correspond  to  the  upper  part 
of  the  Edgewood  limestone.     The  species  are  listed  below : 


ALEXANDRIAN  SERIES  87 

Fossils  from  the  Essex  limestone2* 

Favosites  cf.  niagarensis  Hall  Schuchertella  sp. 

Halysites  catenulatus  Linn  Schuchertella    cf.    subplana     (Con- 
Zaphrentis  sp.  rad) 

Atrypa  marginalis   (Dalman)?  Strophonella  sp. 

Atrypa  cf.  putilla  (Hall  and  Clarke)  Whitfieldella  cf.  cylindrica  Hall 

Atrypa  sp.  Whitfieldella  sp. 

Camarotoechia  near  acinus  Hall  Bellerophon  sp. 

Camarotoechia?  cliftonensis  Foerste  cf.  Cyclora  alta 

Dalmanella  elegantula  var.  Conularia  sp. 

Gypidula  sp.  Diaphorostoma  sp. 

Leptaena  rhomboidalis   (Wilckens)  Pleurotomaria  sp. 

Rhipidomella  hybrida   (Sowerby)  Loxonema  sp. 

Rhynchotreta  lepida  n.sp.  Mytilarca  cf.  mytiliformis   (Hall) 

Rhynchotreta  simplex  Foerste.  Modiolopsis  sp. 
Rhynchotreta  thebesensis  Foerste 

Of  the  fossils  of  the  Essex  limestone,  Atrypa  putilla  and  Rhyncho- 
treta thebesensis  are  common  Edgewood  species  that  are  not  known  in 
the  higher  Sexton  Creek  (Brassfield)  limestone.  Abundant  also  in  the 
Essex  limestone  are  Camarotoechia?  cliftonensis,  Rhynchotreta  simplex, 
and  other  species  that  have  not  been  found  in  the  Edgewood  limestone  of 
Missouri  and  Illinois,  but  which  occur  in,  or  more  probably  immediately 
below,  a  limestone  containing  Brassfield  fossils  in  western  Tennessee. 

The  strata  below  number  1  of  the  section  could  not  be  seen  at  this 
place,  and  60  rods  farther  down  the  creek  a  thickness  of  14  feet  of  Ma- 
quoketa  shale  is  exposed  with  no  overlying  limestone. 

The  Essex  limestone  is  thought  to  represent  a  distinct  formation,  al- 
though its  contact  with  the  overlying  Sexton  Creek  limestone  is  not  clearly 
exposed.  Later  studies  may  show  that  it  should  be  regarded  as  a  member 
of  the  latter  formation  or  more  probably  of  the  Edgewood.  It  occurs 
below  the  Pentamerella?  manniensis  horizon  which,  further  south  in  Illi- 
nois and  Missouri  marks  the  basal  layers  of  the  Sexton  Creek  limestone, 
and  are  separated  from  the  Bowling  Green  member  of  the  Edgewood  lime- 
stone by  a  sedimentary  break.  The  Essex  limestone  is  thus  seen  to  be 
older  than  the  basal  layers  (containing  Pentamerella?  manniensis)  of  the 
Sexton  Creek  limestone  of  Missouri  and  Illinois. 

Sexton  Creek  (Brassfield)   Limestone 

occurrence  and  stratigraphic  relations 

The  name  Sexton  Creek  limestone  was  taken  from  Sexton  Creek  in 

northwest  Alexander  County,  Illinois,  along  which  stream  these  rocks  are 

well   developed   and   exposed.     These    strata   which   are   considered   the 


24The  species  of  fossils  from  the  Essex  and  the  Sexton  Creek  limestones  will  be  figured 
and  described  in  a  paper  now  in  preparation  dealing  with  the  stratigraphy  and  paleontology 
of  these  formations. 


88  BIENNIAL  REPORT 

equivalent  in  time,  of  some  part  of  the  Brassfield  east  of  the  Cincinnati 
axis,  overlap  the  Edgewood  limestone  on  the  east  and  north  in  the  Missis- 
sippi River  region,  and  on  the  south  and  east  in  northeast  Illinois.  They 
probably  transgressed  the  Edgewood  strata  over  all  the  area  of  its  distri- 
bution, but  on  account  of  greater  uplift  along  the  west  part  of  the  Missis- 
sippi River  area  in  post-Sexton  Creek  time,  these  strata  have  been  de- 
nuded from  a  considerable  part  of  eastern  Missouri. 

DETAILED    SECTIONS 

The  lower  layers  of  the  Sexton  Creek  limestone,  containing  Pcnta- 
merella?  mannicnsis,  are  present  south  of  Clarksville,  in  Pike  County, 
Missouri,  and  across  Mississippi  River  near  Belleview,  and  near  Grafton 
in  Jersey  County,  Illinois.  The  Sexton  Creek  limestone  is  well  developed 
in  Calhoun  and  Pike  counties,  Illinois,  as  shown  in  the  following  section  of 
strata  exposed  in  the  vicinity  of  Hamburg  and  Pleasant  Hill. 


i& 


Section  of  strata  in  the  vicinity  of  Hamburg,  Illinois 

Thickness 
Ft.  In. 
Middle  Devonian  (Iowa  Hamilton)  limestone — 

5.     Coarse-grained,   gray  limestone,    containing   Spirifer  iowensis 

and  other  fossils  of  the  Iowa  Hamilton 4        — 

(A  long  break  in  deposition) 
Sexton  Creek  (Brassfield)  limestone — 

4.     Hard,  gray  limestone  in  layers  6  to  30  inches  thick,  contain- 
ing the  greater  number  of    fossils  listed  in  column   1   of 

a    following   table 48        — 

(A  break  in  deposition) 

Edgewood  limestone — 

3.     Yellow  to  brown  limestone  which  on  weathering  breaks  into 
thin    slabs    in    an    almost   vertical   direction ;    fossils    few. 

( Bowling  Green  member) 16        — 

2.     Light  gray  oolite,   containing   fossils    similar  to   those   in  the 
middle  parts  of  the  oolite  at  Louisiana,  Missouri.     (Noix 

oolite  member) 3        6 

(A  break  in  deposition) 
Maquoketa  shale — 

1.     Bluish,  plastic  shale,  without  fossils,  exposed 7        - 

The  basal  layers  of  the  Sexton  Creek  limestone  in  this  region,  both 
in  Missouri  and  Illinois,  are  marked  by  numerous  shells  of  Pentamerella? 
mannicnsis  Foerste  and  a  species  of  Pcntamcrus.  A  narrow  zone,  18  to 
20  feet  below  the  top  of  the  formation  contains  Rhinopora  near  verrucosa, 
Stricklandinia  triplesiana,  Stricklandinia  n.sp.,  and  Triplecia  ortoni.    The 


ALEXANDRIAN  SERIES  89 

upper  10  feet  of  this  limestone  furnished  Syringolites  cf.  huronensis  and 
Spirifcr  radiatus.  The  fauna  of  the  Sexton  Creek  limestone  in  this  vicin- 
ity is  shown  in  the  table  of  fossils  on  a  later  page. 

In  northeast  Illinois  the  Sexton  Creek  limestone  is  thought  to  be 
present  over  a  considerable  area  in  Will  and  Kankakee  counties  and  far- 
ther north  in  the  State.  A  succession  of  strata  very  similar  to  that  de- 
scribed in  the  last  section  occurs  along  the  east  bank  of  Kankakee  River, 
3  to  4  miles  above  Custer  Park,  in  Will  County,  as  shown  in  the  section 
given  below : 

Section  of  strata  along  the  Kankakee  River,  above  Custer  Park 

Thickness 
Ft.  In. 
Sexton  Creek   (Brassfield)    limestone — 

4.     Hard,  gray,  rather  massive  limestone,  containing  many  fossils 

at  certain  levels 18-28        - 

(A  probable  break  in  deposition) 
Edgewood  limestone(?)  — 

3.     Yellow  to  brown  earthy  limestone,  with  few  or  no  fossils 4        6 

2.     Reddish-brown,  iron-stained  oolite   (Noix  oolite  member)....   3         9 
(A  break  in  sedimentation) 
Maquoketa  shale — 

1.     Bluish-gray,  plastic  shale,  with  no  fossils 4-8        - 

In  the  upper  part  of  the  Sexton  Creek  limestone  exposed  at  this  place 
is  a  layer  containing  Clathropora  cf.  frondosa,  Rhino  p  or  a  near  verrucosa, 
Stricklandinia  n.sp.,  and  Triplccta  ortoni,  which  corresponds  with  the 
layer  containing  similar  fossils,  and  occurring  18  to  20  feet  below  the  top 
of  the  Sexton  Creek  limestone  in  the  vicinity  of  Hamburg,  and  in  the 
lower  part  is  a  layer  containing  Pentamerella?  manniensis. 

In  the  following  table  of  fossils,  a  cross  in  the  first  column  opposite 
the  name  indicates  that  the  species  was  found  in  the  Sexton  Creek  lime- 
stone in  the  vicinity  of  Hamburg  and  Pleasant  Hill,  and  a  corresponding 
cross  in  the  second  column  shows  that  the  species  was  obtained  from  the 
Sexton  Creek  limestone  below  Custer  Park. 


90 


BIENNIAL   REPORT 


Fossils  from  the  Sexton  Creek  limestone 


FOSSILS 


bo 

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X 

X 
X 
X 
X 
X 
X 
X 
X 
X 

X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 

X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 

X 

X 

X 

X 

X 

X 

X 
X 

X 

X 

X 
X 

X 

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X 

X 

X 

X 

X 

X 

X 

X 

Clathrodictyon  vesiculosum  Nicholson  and  Murie 

Diphyphyllum  caespitosum   Hall 

Favosites  favosus  Goldfuss 

Halysites  catenulatus  Linnaeus 

Lyellia    sp , 

Syringolites  cf .   huronensis  Hinde 

Syringopora    sp 

Syringostroma   sp 

Thecia    sp 

Zaphrentis  sp 

Callopora  sp 

Phoenopora  sp  

Rhinopora  near  verrucosa  Hall 

Rhinopora   sp 

Atrypa  marginalis    (Dalman)  ? 

Atrypa   reticularis   Linnaeus , 

Camarotoechia  acinus  var.  convexa  Foerste 

Camarotoechia  sp 

Clorinda    sp 

Dalmanella  elegantula   (Dalman) , 

Dalmanella    sp 

Leptaena  rhomboidalis    (Wilckens) 

Orthis  flabellites  Foerste 

Pentamerella  ?  manniensis  Foerste 

Pentamerus  oblongus   Sowerby 

Pentamerus    sp 

Platystrophia  daytonensis   Foerste 

Platystrophia    reversata    Foerste 

Plectambonites  cf.  transversalis  var.  elegantula  Foerste 

Schuchertella    sp 

Spirifer  radiatus  Sowerby 

Stricklandinia    triplesiana    Foerste , 

Stricklandinia     sp 

Stropheodonta   sp 

Strophonella   filistriata    Foerste 

Strophonella  cf.   roemeri  Foerste 

Triplecia  ortoni  Meek 

Whitfieldella  sp 

Diaphorostoma  cf.  niagarensis   (Hall) 

Amphicoelia  cf.  leidyi  Hall 

Dawsonoceras    sp 


ALEXAXDRIAX  SERIES 


91 


Fossils  from  the  Sexton  Creek  limestone — Concluded 


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FOSSILS 

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Orthoceras    sp 

Bronteus  acamus  Hall 

Ceraurus  cf.  niagarensis  Hall.. 

Encrinurus    sp 

Illaenus  ambiguus  Foerste 

Illaenus  cf.  daytonensis  Foerste. 
Illaenus  madisonianus  Whitfield 
Illaenus  sp 


In  the  above  list  the  greater  number  of  fossils  to  which  no  specific 
names  are  given  are  new.  The  similarity  of  the  faunas  of  the  Sexton 
Creek  limestone  in  the  vicinity  of  Hamburg  and  above  Custer  Park  along 
Kankakee  River  indicates  that  the  strata  at  the  two  localities  are  equiva- 
lent. 

The  presence  in  the  Sexton  Creek  limestone  of  such  characteristic 
Brassfield  species  as  Clathropova  cf.  frond osa,  Rhino pora  near  verrucosa, 
Camarotoechia  acinus  var.  convexa,  Strophonclla  fdistriata,  Stricklandinia 
triplesiana  and  Triplecia  ortoni  indicates  that  the  Sexton  Creek  limestone 
in  the  Mississippi  valley  represents  about  the  same  general  period  of  depo- 
sition as  the  Brassfield  limestone,  east  of  the  Cincinnati  axis,  in  Ohio. 


Gexeral  Coxclusioxs 

It  should  be  noted  that  the  fauna  of  the  Sexton  Creek  limestone  in 
Mississippi  Valley  lacks  several  species  that  are  present  in  the  Brassfield 
limestone  in  Ohio,  such  as  Pachydictya  bifurcata,  Phacnopora  magna, 
Camarotoechia?  scobina,  Dalmanites  werthneri,  Cyphaspis  clintonensis. 
A  number  of  fossils  not  found  in  the  Brassfield  limestone  east  of  the  Cin- 
cinnati anticline  are  present  in  the  Sexton  Creek  limestone  of  Illinois  and 
Missouri,  among  which  are  Callopora  n.  sp.,  Rhinopora  n.sp.,  Pentamerus 
oblongus,  Spirifer  radiatus,  Stricklandinia  n.sp.,  Amphicoelia  cf.  leidyi 
and  Bronteus  acamus. 

Although  the  basins  in  which  the  Sexton  Creek  limestone  of  the 
Mississippi  valley  region  and  the  Brassfield  limestone  of  the  Ohio  region 
were  deposited  are  both  thought  to  have  had  a  southward  sea  connection, 
the  difference  in  the  faunas  of  this  time  in  the  two  areas  is  interpreted 
as  indicating  the  presence  between  them  of  a  land  barrier  (the  enlarged 


92  BIENNIAL  REPORT 

Cincinnati  anticline)  extending  sufficiently  far  to  the  south  to  prevent 
the  easy  intermigration  of  the  organisms  from  one  basin  to  the  other, 
and  thus  permitted  the  development  in  them  of  somewhat  different  faunas. 
For  the  basin  connecting  southward  with  the  wider  sea  of  the  Tennessee 
and  Arkansas  region,  in  which  the  Alexandrian  strata  in  Illinois  and 
Missouri  were  laid  down,  the  name  ''Illinois  basin"  is  here  proposed. 
This  basin  is  thought  to  have  been  a  northwardly  extending  embayment, 
and  a  distinct  area  of  sedimentation  during  the  time  of  deposition  of  all 
of  the  strata  in  this  region  from  the  beginning  of  the  Thebes  sandstone 
to  the  end  of  the  Sexton  Creek  limestone. 

During  Alexandrian  time  the  Illinois  basin  had  a  widely  open  typical- 
ly marine  southern  connection  with  the  Gulf  region,  and  from  the  Tennes- 
see area  another  bay,  known  as  the  Brassfield,  extended  widely  east  of 
the  Cincinnati  axis  in  Ohio  and  Kentucky.  The  early  Silurian  sea 
gained  access  to  the  Illinois  and  Missouri  region  earlier,  and  probably  con- 
tinued later,  than  in  the  region  east  of  the  Cincinnati  axis.  Several  of 
the  genera  and  a  number  of  the  species  of  fossils  that  occur  in  the  Brass- 
field  limestone  in  Ohio  were  introduced  a  little  earlier  into  the  Illinois 
basin,  appearing  in  late  Edgewood  time.  In  the  upper  part  of  the  Sexton 
Creek  limestone,  there  are  a  few  species  that  do  not  appear  east  of  the 
Cincinnati  axis  until  post-Brassfield  time. 

In  the  fauna  of  the  Edgewood  limestone  there  can  be  recognized  an 
element  that  was  derived  from  that  of  the  Girardeau  limestone;  and  in 
the  Sexton  Creek  fauna  there  appears  a  still  larger  element  that  was 
present  in  the  earlier  Edgewood  limestone.  The  Alexandrian  series  in 
the  Illinois  basin  is  thus  shown  to  consist  of  a  number  of  closely  related 
early  Silurian  formations  which  record  a  succession  of  oscillatory  north- 
ward sea  advances  that  are  seemingly  separated  one  from  another  by  sedi- 
mentary breaks  due  to  temporary  sea  withdrawal.  The  earliest  of  these 
invasions,  represented  by  the  Girardeau  limestone,  was  the  least  extensive. 
The  deposits  of  each  succeeding  invasion  reached  farther  north  and  were 
spread  more  widely  than  those  of  the  preceding,  this  cycle  of  early  Silurian 
sedimentation  in  this  region  culminating  in  the  Sexton  Creek  submer- 
gence. 

The  relations  of  the  Alexandrian  formations  described  above  are 
shown  in  the  following  composite  section. 


ALEXANDRIAN  SERIES 


93 


Generalised  section  of  the  Alexandrian  strata  in  Missouri  and  Illinois 


Location    of    ex- 
posures 


Description  of  horizons 


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4c.  Light-gray,  hard,  thick-bedded  limestone  with 
Syringolites  cf.  hnronensis  and  Spirifer  radi- 
atus,  10  feet,  in  Calhoun  and  Pike  counties. 
Pink  limestone,  23  feet,  in  Alexander  County, 
Illinois 10   to   23    feet 


4b.  Light-gray,  hard  limestone,  fossils  numerous  in 
certain  layers.  Rhinopora  near  verrucosa,  Cam- 
arotoechia  acinus  var.  convexa,  Straplionella 
Mistriata,  Stricklandinia  triplesiana,  Strickland- 
inia  n.sp.  and  Triplecia  cf.  ortoni  common  about 
10  feet  below  the  top,   about 34  feet 


4a.     Light-gray       or 

Pcntamerella? 


brown  limestone  containing 
manniensis  and.  Pentamerns 
1   foot,   6   inches 


A  possible  break  in  deposition 


94 


BIENNIAL  REPORT 


Generalised  section  of  the  Alexandrian  strata  in  Missouri  and  Illinois 

— Concluded 


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Description   of  horizons 


3a.  Yellowish  brown,  magnesian  limestone  above, 
bluish  shaly  limestone  below,  in  layers  3  to  9 
inches  thick.  Atrypa  putilla,  Camarotoechiaf 
cliftonensis,  Rhynchotreta  simplex,  R.  thebes en- 
sis,  Schnchertella  cf.  subplana  and  other  fos- 
sils   10   feet.   6   inches 


A  possible  break  in  deposition 


2b.  Bluish  to  brown  impure  limestone  in  layers  3 
to  36  inches  thick,  with  few  fossils  (Bowling 
Green  member) 15   to  35   feet 


2a.  Gray  to  brown  limestone,  the  upper  layer  in 
places  containing  Calapoccia  favostoidea,  Favos- 
itcs  subclongus,  WhitHeldclla  oroides,  and  Cyclo- 
iicma,  day  tone  nsis.  Below  this  Atrypa  prae- 
marginalis,  A.  putilla,  Camarotoechiaf  concinna, 
Dalmanella  edgewoodensis  and  Whitheldella 
billingsana.  The  lower  layers  with  Dalmanites 
danai    and    Shuchcrtella   propinqua    common    (Cy- 

rene  member) 8  to   15   feet 

The   upper   one-half  to   two-thirds   of  this   mem- 
ber is  oolitic  (Noix  oolite)  near  Mississippi  River. 


A    break    in    sedimentation 


1.  Fine-grained,  dark  limestone,  in  layers  1  to  5 
inches  thick,  with  Ptychocrinus  splendens, 
Rafinesquinaf  mesicosta,  Schuchertella  missou- 
riensis,  Protozeuga  sulcocarinata  and  Comulites 
incurvus 33  to  38  feet 


A   break   in    sedimentation 


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ALEXANDRIAN  SERIES  95 

PALEONTOLOGY    OF    THE    GIRARDEAU    AXD    EDGEWOOD 

LIMESTONES 

Introductory  Statement 

The  paleontological  portion  of  this  paper  deals  only  with  the  species 
of  fossils  from  the  Girardeau  limestone,  and  the  Edgewood  formation. 
The  fossils  from  the  Essex  and  Sexton  Creek  limestones  will  be  figured 
and  described  in  a  later  paper,  now  in  preparation.  The  field  study  and 
collection  of  fossils  on  which  this  work  is  based  were  made  by  the 
writer  under  the  auspices  of  the  Illinois  Geological  Survey,  the  many 
favors  of  which  organization  are  here  gladly  acknowledged.  The  fossils 
were  mostly  obtained  from  the  following  localities.  Those  of  the  Girard- 
eau limestone  came  from  exposures  a  few  miles  north  and  south  of 
Thebes,  Illinois,  and  north  of  Cape  Girardeau,  Missouri.  Those  from 
the  Edgewood  limestone  were  mostly  obtained  from  outcrops  of  those 
strata  in  Alexander  and  Calhoun  counties,  Illinois,  and  from  near  the 
towns  of  Edgewood,  Cyrene,  Watson  Station,  and  between  Clarksville 
and  Kissenger  in  Pike  County,  Missouri ;  those  from  the  Channahon 
limestone  member  were  found  in  the  south  bank  of  Desplaines  River 
about  one  mile  southeast  of  Channahon  in  Will  County,  Illinois.  Unless 
otherwise  stated,  the  type  specimens  of  the  new  species  herein  described 
are  in  the  possession  of  the  writer  at  the  University  of  Illinois. 

The  drawings  of  the  fossils  used  in  the  illustrations  were  made  by 
W.  C.  Matthews  and  S.  Fred  Prince. 

The  writer  is  also  indebted  to  Professor  Stuart  Weller  and  Dr. 
A.  R.  Crook  for  the  loan  of  type  specimens  of  fossils  in  the  collections 
of  the  University  of  Chicago  and  the  Illinois  State  Museum,  respectively, 
from  the  formations  studied,  some  of  which  were  figured  for  illustration 
in  this  work. 

The  complete  synonymy  and  bibliography  of  the  more  common  old 
species  of  brachiopods  are  not  given,  as  the  student  can  readily  find  them 
in  Bulletin  87  of  the  United  States  Geological  Survey. 

Descriptions  of  Species  from  the 
Girardeau  Limestone 

Echinodermata 

Crinoidea 

Ptychocrinus  splendens  (S.  A.  Miller) 

(Plate  III,  figure  1) 

1883.     Gaurocrinus  splendens.     S.  A.  Miller,  Jour.  Cincinnati  Soc.  Nat.  Hist.,  vol. 

6,  p.  230,  pi.  2,  figure  3. 
1885.     Ptychocrinus  splendens.     W.  and  Sp.,  Revision  Paleocr.,  Part  3,  p.  101. 


96  BIENNIAL  REPORT 

1889.     Gaurocrinus  splendens.     S.  A.  Miller,  N.  Amer.  Geol.  and  Paleont,  p.  247. 
1897.     Ptychocrinus  splendens.     W.  and  Sp.,  Crinoidea  Camerata  of  N.  Amer.,  p. 
198. 

Miller's  description :  "Column  small,  round,  and  composed  of  alternately 
thinner  and  thicker  plates.  Basals  small,  showing  upon  the  outer  surface  a  low 
triangular  outline,  slightly  truncated  laterally.  Subradials  large,  hexagonal,  longer 
then  wide,  and  not  truncated  upon  the  upper  face  by  an  interradial.  Surface 
mounted  by  a  strong  semi-cylindrical  ridge  which  bifurcates  in  the  upper  part, 
and  sends  an  arm  to  the  adjoining  first  radials,  and  extends  downward  like  a 
tubercle  below  the  point  of  union  between  the  column  and  basal  plates. 

"First  primary  radials  about  as  large  as  the  subradials,  as  long  as  wide, 
heptagonal.  Second  radials  hexagonal,  longer  than  wide.  Third  about  the  same 
size  as  the  second,  and  not  truncated  by  the  axillary  plate.  Secondary  radials  three 
or  four  by  ten,  the  arms  not  bifurcating  at  the  top  of  the  vault,  but  continuing, 
without  bifurcation,  to  the  twelfth  or  fourteenth  plate. 

"First  interradial  plate  large,  tuberculated,  and  followed  by  two  smaller 
plates,  and  these  by  three,  and  so  on  to  the  top  of  the  calyx,  each  bearing  an 
elongated  central  tubercle.     Intersecondary  plates  of  the  same  character. 

"Pinnules  directed  straight  from  each  side,  showing  that  they  do  not  cover 
the  ambulacral   furrows. 

"The  calyx  is  elongated  and  strongly  pentagonal.  The  radial  series  stand  out 
in  bold  cylindrical  columns,  while  the  interradial  spaces  are  abruptly  and  deeply 
sunken." 

Specimens  of  this  species  are  in  some  places  very  numerous  in  the 
calcareous  shale  partings  between  the  layers  of  the  Girardeau  limestone, 
south  of  Thebes,  Illinois. 

Cyclocystoides  illinoisensis  Miller  and  Gurley 
(Plate  III,  figure  2) 
1895.     Cyclocystoides  illinoisensis.     Miller  and    Gurley,    Bull.    Illinois    State   Mus. 
Nat.  Hist.,  No.  6,  p.  61,  pi.  6,  figures  27  and  28. 

Miller  and  Gurley' s  description :  "This  species  is  large  and  the  outer  rim 
is  composed  of  a  great  many  plates.  One  of  our  specimens  which  does  not  appear 
to  be  more  than  one-third  of  a  circle,  has  nine  plates.  The  other  specimen,  which 
does  not  appear  to  be  much,  if  any,  more  than  one-half  of  the  circle,  has  thirteen 
plates.  The  inference  is  that  a  complete  specimen  will  have  from  twenty-four 
to  thirty  plates.  The  outer  part  of  the  margin  of  the  rim  bears  four  or  five  rows 
of  elongated  nodes,  such  as  have  not,  we  believe,  been  heretofore  found  on  any 
specimen. 

"The  great  number  of  plates,  in  the  rim,  and  the  elongated  nodes  on  the  mar- 
gin will  distinguish  this  species   from  all  that  have  been  heretofore  described. 

"Found  in  the  Hudson  River  Group  on  Orchard  Creek,  Alexander  County, 
Illinois." 

This  species  is  known  only  from  the  Girardeau  limestone  in  Alex- 
ander County,  Illinois,  where  it  is  of  rare  occurrence. 


ALEXANDRIAN  SERIES  97 

Vermes 

Annulosa 

Comulites  incurvus   (Shumard) 

(Plate  IV,  figure  7) 

1855.     Tentaculitcs  incurvus.     Shumard,  Ann.  Rep.  Geol.  Surv.  Missouri,   1  and  2, 

p.  195,  pi.  B,  figures  6a,  6b. 

Shumard's  description  :     "Tube  attenuated,  curved,  with  prominent  sharp  an- 

nulations  extending  to  the  tip  ;   at  the  large  extremity  there  are  from  five  to  six 

rings  in  the  space  of  an  eighth  of  an  inch,  and  the  intervening  spaces  are  about 

double  the  width ;  but  near  the  tip  the   rings  are  much  closer  together,  and  there 

are  from  eighteen  to  twenty  in  the  eighth  of  an  inch ;  the  whole  number  of  rings 

amounts  to  about  thirty-five.     The  surface  is  covered  with  fine  longitudinal  striae, 

which   cross  the   rings,   as  well   as  the   spaces.     In  well   preserved   specimens  very 

fine  transverse   striae  can  be  perceived.     The   length  of  the   tube  varies   from   six 

to  eight  lines. 

"These  little  bodies  occur  on  the  Mississippi,  two  miles  above  Cape  Girard- 
eau, in  the  Cape  Girardeau  limestone.  They  occur  in  the  greatest  profusion, 
associated  with  Encrinurus  deltoideus,  Cyphaspis  girardcauensis,  and  Proetus 
depressus." 

This  species  resembles  C.  sterlingensis  Meek  and  Worthen  from  the 
Maquoketa,  in  size  and  general  appearance,  but  can  be  distinguished  from 
the  latter  by  the  greater  distance  between  the  annulations  and  by  the 
continuation  of  the  longitudinal  striae  over  the  annulations.  It  is  allied 
to  C.  distans  Hall,  but  differs  from  it  in  the  less  rapid  expansion  of  the 
shell,  and  in  being  curved  instead  of  straight. 

Comulites  tenuistriatus  (Meek  and  Worthen) 

(Plate  IV,  figure  6) 

1865.     Tentaculitcs  tenuistriatus.     Meek  and  Worthen,  Proc.  Acad.  Nat.  Sci.,  p.  254. 

1868.     Tentaculitcs  tenuistriatus.     Meek    and    Worthen,    111.    Geol.    Survey,    vol.    3, 

p.  341,  pi.  4,  figures  7a,  7b. 

Meek  and  Worthen's  description  :  "Shell  attaining  a  rather  large  size,  grad- 
ually tapering,  and  a  little  curved ;  annulations  large,  prominent,  rather  obtuse  near 
the  smaller  end;  separated  by  rounded  constrictions  of  about  0.10-inch  breadth  at 
the  larger  extremity  of  a  specimen  one  inch  or  more  in  length.  Surface  marked 
by  numerous,  very  fine,  regular,  closely  arranged  longitudinal  striae,  most  dis- 
tinctly marked  in  the  rounded  depressions  between  the  annulations.  Aperture  cir- 
cular. Length  1.16  inches;  breadth  at  the  aperture,  measuring  upon  one  of  the 
rings,  0.25  inch;  do.  between  the  rings  0.19  inch;  space  occupied  by  four  rings, 
and  the  three  intervening  spaces  at  the  larger  end,  0.30  inch ;  while  the  same  space 
includes  six  rings  at  the  smaller  end. 

"Locality  and  Position :  Cincinnati  Group  of  Lower  Silurian  series ;  Alex- 
ander County,  Illinois." 

The  authors  of  this  species  note  the  fact  that  it  resembles  the 
enlarged  figure  of  Comulites  flexuosus  Hall,  but  differs   from  it  in  its 


98  BIENNIAL  REPORT 

larger  size,  in  having  sharper  ambulations,  and  more  crowded  longitudinal 
striae.  This  form,  is  in  some  respects,  like  Cormdites  incurvus,  from 
which  it  is  readily  distinguished  by  its  much  larger  size,  the  greater  width 
between  the  ambulations  and  the  absence  of  annular  striae.  It  is  not  un- 
common in  the  Girardeau  limestone,  in  Illinois. 

Molluscoidea 
Bryozoa 
Nematopora  alternata  Ulrich 
(Plate  III,  figure  6) 
1890.     Nematopora  alternata.     Ulrich,   111.  Geol.  Survey,  vol.  8,  p.  646,  pi.  29,  fig- 
ures 8-8a. 
Ulrich's  description  :     "In  growth  and  general  aspect  this   species  closely  re- 
sembles Ar.  retrorsa,  and  in  the  worn  condition  in  which  the  specimens  are  usually 
found,  it  is  not  easy  to  distinguish  them.     When  in  a  good  state  of  preservation, 
the  alternate  arrangement  of  the  cells,  absence  of  longitudinal  separating  carinae, 
and  other  characters  shown  in  the  figure,  will  separate  them. 
"Position  and  locality:     Associated  with  N.  retrorsa." 

This  species  is  not  rare  in  the  Girardeau  limestone  in  Alexander 
County,  Illinois,  where  it  is  associated  with  N.  fragilis,  N.  delicatula  and 
N.  retrorsa. 

Nematopora  delicatula  Ulrich 
(Plate  III,  figure  4) 
1890.     Nematopora  delicatula.     Ulrich,  111.  Geol.   Survey,  vol.  8,  p.  646,  pi.  29,  fig- 
ures 11-1 lb. 
1893.     Nematopora  delicatula.    Ulrich,  Geol.  and  Nat.  Hist.  Survey  of  Minn.,  vol.  3, 

pt.  1,  p.  206,  pi.  3,  figures  26  and  27. 
1897.  Nematopora  delicatula.  Simpson,  fourteenth  Ann.  Rept.  N.  Y.  State  Geol., 
1894,  p.  553,  figures  124  and  125. 
Ulrich's  description :  "Zoarium  small,  exceedingly  slender,  ramose  above  the 
pointed  basal  end.  Branches  quadrangular,  each  side  0.15  to  0.18  mm.  wide.  Zooecia 
in  four  ranges,  with  subcircular  or  ovate  aperture,  0.12  mm.  in  the  largest  diameter, 
separated  by  long  intervals,  about  three  in  0.2  mm.  Peristome  very  faint,  often 
confluent  with  the  moderately  sharp  angles  of  the  branches. 

"The  exceeding  delicacy,  widely  separated  zooecial  apertures,  and  quadrangular 
zoarium  of  this  species,  distinguish  it  from  all  other  species  of  the  genus,  excepting 
N.  quadrata  known  to  me.     It  is  too  distinct  from  that  form  to  require  comparison. 
"Position   and   locality :     Associated    with   the   preceding   species    in   the    Cin- 
cinnati group,  Alexander  County,  Illinois." 

This  little  species  occurs  in  considerable  abundance  in  the  Girardeau 
limestone,  in  Illinois. 


ALEXANDRIAN  SERIES  99 

Nematopora  fragilis  Ulrich 
(Plate  III,  figure  3) 
1890.     Nematopora  fragilis.     Ulrich,    111.    Geol.    Survey,   vol.   8,   p.    646,   pi.   29,   fig- 
ures 9-9b. 

Ulrich's  description :  "Zoarium  ramose,  very  slender,  branching  dichotom- 
ously  or  otherwise ;  branches  0.35  mm.  in  diameter.  Zooecia  in  six  longitudinal 
ranges,  seven  in  four  mm. ;  ranges  not  separated  by  a  ridge,  though  the  branch 
looks  angular  when  worn.  Apertures  ovate,  0.08  mm.  in  width,  twice  as  long,  and 
channeled  posteriorly;  a  faint  peristome  around  the  sides  and  front  margins.  In 
vertical  sections  the  walls  are  thin  and  falciform.  Transverse  sections  show  two 
minute  axial  tubes  at  the  center  of  the  branch. 

"The  six  ranges  of  zooecia  suggest  a  comparison  with  N.  Uneata  Billings, 
from  the  Anticosti  group,  but  we  soon  find  that  they  disagree  in  nearly  every  other 
respect.  The  species  finds  closer  allies  in  N.  retrorsa  and  N.  alternata  but,  when 
in  a  good  state  of  preservation,  the  different  form  of  aperture,  smaller  size  of 
branches  and  other  characters   readily  distinguish  them. 

"Position  and  Locality :  Base  of  Cincinnati  group ;  Alexander  County, 
Illinois." 

This  species  has  a  general  resemblance  to  N.  alternata,  from  which 
it  differs,  as  Ulrich  states,  in  the  form  of  the  aperture  and  the  smaller 
size,  and  also  in  the  more  widely  separated  apertures.  It  occurs,  asso- 
ciated with  the  other  species  of  Nematopora,  in  the  Girardeau  limestone. 

Nematopora  retrorsa  Ulrich 
(Plate  III,  figure  5) 
1890.     Nematopora  retrorsa.     Ulrich,   111.    Geol.    Survey,   vol.  8,  p.   645,   pi   29,   fig- 
ures 9-9b. 

Ulrich's  description  :  "Zoarium  ramose,  subcylindrical,  branching  irregularly, 
about  0.6  mm.  in  diameter.  Zooecia  arranged  in  longitudinal  series,  about  5  in  two 
mm.,  between  eight  to  ten  straight  and  moderately  prominent  ridges.  Apertures 
sub-circular,  0.1  mm.  in  diameter,  slightly  truncated,  and  sloping  on  the  posterior 
side ;  the  anterior  margin  direct,  sharp,  sometimes  with  a  perceptible  rim.  Imme- 
diately below  the  orifice  the  interspace  exhibits  three  faint  striae.  Walls  of  zooecia 
very  thin,  appearing  somewhat   sickle-shaped   in  vertical   section. 

"The  backward  direction  and  the  subcircular  form  of  the  zooecial  apertures 
are  characteristic  features.  In  N.  fragilis  the  apertures  are  also  directed  back- 
wards, but  they  differ  in  being  oval,  while  the  longitudinal  ridges  are  less  distinct 
or  absent,  and  the  rows  of  zooecia  only  six  instead  of  eight  to  ten. 

"Position  and  Locality :  Base  of  Cincinnati  group.  Alexander  County, 
Illinois." 

This  elegant  species  is  not  uncommon  in  the  Girardeau  limestone. 
Slabs  of  this  rock  were  found,  on  the  surfaces  of  which  occur  branches 
of  each  of  the  four  species  of  Nematopora  described  from  this  formation. 


100  BIENNIAL   REPORT 

Brachiopoda 

Lingnlops  ovata  n.sp. 
(Plate  III,  figures  7  and  8) 

The  shell  is  small  and  sub-ovate,  somewhat  resembling  L.  whitfieldi 
Hall  of  the  Maquoketa,  but  differing  from  that  species  in  the  more 
elongate  form,  the  more  acuminate  beak,  and  the  more  tapering  anterior 
portion.  It  may  also  be  readily  distinguished  from  L.  norzvoodi  James 
by  the  more  tapering  character  of  the  anterior  and  posterior  ends. 

Shell  widest  a  short  distance  posterior  to  the  middle,  from  whence 
it  tapers  quite  rapidly  to  the  pointed  beak,  and  narrows  more  gently  to 
the  narrowly  rounded  or  sub-truncate  anterior  margin,  as  shown  in  the 
figure.  The  surface  is  marked  by  thin  concentric  lamellae  which,  under 
a  lens,  appear  fibrous  in  structure  and  give  to  a  slightly  weathered  surface 
the  appearance  of  faint  radiating  striae. 

The  dimensions  are:     length,  2  to  3.5  mm.,  width,  1.25  to  2.5  mm. 

Shells  of  the  above  species  are  common  in  the  Girardeau  limestone, 
near  Thebes,  where  they  are  associated  with  Schuchertella  missouriensis, 
Rafincsquina?  mesicosta,  and  other  species  occurring  in  this  formation. 

Rafincsquina?  delicatula25  n.sp. 
(Plate   III,  figure  9) 

The  shells  are  allied  to  R.  mesicosta  (Shumard)  with  which  they  are 
associated,  but  differ  from  that  species  in  the  smaller  size,  the  much  finer 
radiating  striae,  the  absence  of  the  larger  median  stria,  and  the  presence 
(in  some  shells)  of  a  low,  undefined  median  fold  on  the  ventral  valve  and 
a  corresponding  obscure  dorsal  sinus. 

Shells  small,  nearly  semi-ellipitical  in  outline,  the  hinge  line  a  little 
shorter,  equal  to,  or  a  little  longer  than  the  greatest  width  of  the  shell, 
lateral  margins  rounding  to  the  front.  Ventral  valve  slightly  convex, 
often  with  a  rather  broad,  low,  undefined  median  fold.  Beak  small,  not 
projecting  beyond  the  hinge  line.  Dorsal  valve  slightly  concave,  some- 
times with  a  shallow  undefined  furrow  occupying  the  medial  portion. 
Surface  of  both  valves  marked  with  numerous  fine,  unequal,  radiating 
striae  which  divide  two  or  three  times  between  the  beak  and  the  front 
margin.  Entire  surface  crossed  by  numerous  very  fine  concentric  lines 
and  occasional  stronger  lines  of  growth.  The  dimensions  of  average 
shells  are :  length,  4  to  5.5  mm.,  width,  5.5  to  7  mm. ;  thickness,  about 
1.75  mm. 


"'This  species  and  the  following  have  been  referred  to  the  genus  Rafincsquina  because  in 
none  of  the  shells  of  either  species  were  there  seen  crenulations  on  the  hinge  line,  such  as  are 
common  in  shells  of  Silurian  Rafinesquinoids,  and  which  characterize  the  genus  Brachytn'on. 
It  is  possible  that  the  crenulations  are  present  but  obscured  by  the  granular  character  of  the 
rock  in  which  the  shells  are  embedded. 


ALEXANDRIAN  SERIES  101 

This  species  is  common  in  the  Girardeau  limestone,  near  Thebes, 
Illinois.  It  is  readily  distinguished  from  all  other  species  of  Rafinesquina 
by  its  very  small  size,  the  very  fine  radial  and  concentric  markings,  and 
from  R.  mesicosta  by  the  absence  of  a  median  costa  of  larger  size  than 
those  on  either  side. 

Rafinesquina?  mesicosta  (Shumard) 

(Plate  III,  figure  10) 

1855.     Leptaena   mesacosta.     Shumard,    Ann.    Depts.   Mo.   Geol.    Survey,    1    and   2, 

p.  205,  pi.  C,  figure  2. 
1895.     Leptaena  mesacosta.     Keyes,  Mo.  Geol.  Survey,  vol.  5,  p.  76. 

Shumard's  description :  "Shell  small,  subquadrangular,  transverse ;  greatest 
width  at  the  cardinal  border,  which  is  extended  into  small  triangular  ears ;  dorsal 
valve  gently  convex;  beak  pointed,  slightly  prominent,  and  passing  slightly  beyond 
the  cardinal  border;  a  single  longitudinal  rib  extends  from  beak  to  front,  on  either 
side  of  which  the  surface  is  thickly  covered  with  fine  dichotomous  longitudinal 
striae,  of  which  the  number,  two  lines  from  the  beak,  is  about  twelve  in  the  space 
of  one  line ;  longitudinal  striae  crossed  by  very  fine  concentric  striae  of  growth. 
Length,  4  lines ;  greatest  width,  6  lines. 

"Formation  and  Locality :  This  species  is  characteristic  of  the  Cape  Girardeau 
limestone,  on  the  Mississippi  River,  in  Cape  Girardeau  County." 

This  species  is  commonly  associated  with  Schuchertella  missonriensis 
throughout  the  Girardeau  limestone.  It  also  occurs  sparingly  in  the 
succeeding  Edgewood  formation. 

Leptaena  rhomb oidalis  (Wilckens) 
(Plate  III,  figure  11) 

1769.     Conchita    rhomb  oidalis.     Wilckens,    Nachricht    von    selten    Versteinerungen, 
p.  77,  pi.  8,  figures  43,  44. 

1821.     Anomites  rhomb  oidalis.     Wahlenberg,  Acta.  Society  of  Upsala,  vol  3,  p.  65. 

1842.     Strophomena  depressa.     Vanuxem,   Geol.   of  New  York;    Rept.   Third   Dis- 
trict, p.  79,  figure  5. 

1847.     Leptaena  tcnuistriata.     Hall,  Pal.  of  New  York,  vol.  1,  p.  108,  pi.  31a,  figure  4. 

1861.     Strophomena   rhomboidalis.     Billings,    Canadian    Jour.,    vol.    6,    p.    336,    fig- 
ures  111,   112. 

1892.     Leptaena  rhomboidalis.     Hall  and  Clarke,  Pal.  of  New  York,  vol.  8,  pt.   1, 
p.  279,  pi.  8,  figures  17-31 ;  pi.  15a,  figures  40-42;  pi.  20,  figures  21-24. 

1895.     Leptaena  rhomboidalis.     Foerste,  Geol.  Ohio,  vol.  7,  p.  566. 

1909.     Leptaena  rhomboidalis.    Weller,   Bull.   Geol.    Soc.   America,  vol.  20,  p.  292, 
pi.  12,  figures  2,  3. 

Shell  has  a  straight  hinge  line  which  is  a  little  longer  than  the  greatest 
width  of  the  shell  below,  transversely  subelliptical  in  outline,  geniculate 
at  about  two-thirds  of  the  distance  from  the  beak  to  the  margins.  Ventral 
valve  convex  in  the  umbonal  region,  gradually  becoming  flatter  toward 
the  geniculate  portion.     This  portion  of  the  shell  is  bent  abruptly  towards 


102  BIENNIAL   REPORT 

the  dorsal  valve  at  an  angle  of  about  90  degrees.  Posterior  to  the  genicu- 
lation  the  surface  of  the  valve  bears  6  to  8  prominent,  somewhat  discon- 
tinuous, concentric  wrinkles  which,  near  the  cardino-lateral  margin  bend 
outward  toward  the  cardinal  extremities.  Besides  the  concentric  wrinkles,, 
the  surface  is  marked  by  numerous  fine  radiating  striae,  which  are  crossed 
by  very  fine  concentric  lines.  Neither  the  cardinal  area  nor  the  surface 
of  the  dorsal  valve  is  exposed  in  the  specimens  found  in  the  Girardeau 
limestone. 

The  dimensions  are :  length  to  the  geniculation,  about  10  mm. ; 
width,  about  18  mm. 

Imperfect  shells  of  this  species  are  not  rare  in  the  Girardeau  lime- 
stone, both  north  and  south  of  Thebes,  Illinois. 

Schuchertella  missouriensis  (Shumard) 

(Plate  III,  figures  12  and  13) 

1855.     OrtJiis    missouriensis.     Shumard,   Ann.    Repts.    Mo.   Geol.    Survey,    1    and   2, 

p.  205,  pi.  C,  figures  9a-b. 
1895.     Or  this  missouriensis.     Keyes,  Mo.  Geol.   Survey,  vol.  5,  p.  60. 

Shumard's  description:  "Shell  transverse,  semi-elliptical,  depressed  convex - 
cardinal  margin  equal  to  the  greatest  width  of  the  shell ;  dorsal  valve  very  gently 
convex,  with  a  broad  and  very  shallow  sinus ;  beak  pointed,  flattened,  and  not 
extending  beyond  the  cardinal  border;  surface  covered  with  fine,  sharp,  rounded, 
simple  ribs,  with  interstitial  ribs  often  planted  between,  which,  before  reaching 
the  border,  attain  the  same  size  as  the  regular  ones ;  the  number  on  the  border 
amounts  to  fifty  or  sixty.  With  the  assistance  of  the  lens  we  can  perceive  numer- 
ous very  fine  concentric  striae,  which  give  to  the  surface  a  very  elegant  appearance. 

"Formation  and  Locality :  Occurs  in  the  Cape  Girardeau  limestone  on  the 
Mississippi  river,  two  miles  above  Cape  Girardeau." 

In  many  of  the  shells  of  this  species  from  the  Girardeau  limestone  the 
radiating  striae  are  arranged  in  groups  of  three  very  fine  striae,  the  groups 
being  separated  by  a  single  stria  of  considerably  larger  size.  In  some  of 
the  shells  the  middle  one  of  the  group  of  three  fine  striae  is  larger  than 
the  other  two,  so  that  every  alternate  stria  is  larger  than  the  one  between 
them. 

This  species  is  very  abundant  in  the  Girardeau  limestone  in  Alex- 
ander County,  Illinois,  and  shells  that  are  scarcely  distinguishable  from 
this  species  occur  also  in  the  Edgewood  limestone  in  Pike  County, 
Missouri. 

Dalmanella  modesta  n.sp. 
(Plate  III,  figures  14  and  15) 
In  some  features  this  shell  resembles  Dalmanella  elegantula   (Dal- 
man)    from  which  it  is  distinguished  by  its  more  transverse   form,  its 


ALEXANDRIAN  SERIES  103 

coarser  striae,  the  smaller  number  of  radiating  striae  that  terminate  on 
the  cardinal  line,  and  the  less  highly  arched  ventral  valve. 

Shell  lenticular  or  slightly  convex,  transversely  semi-elliptical  in  out- 
line, a  little  wider  than  long ;  hinge  line  nearly  as  long  as  the  greatest 
width  of  the  shell.  Ventral  valve  convex,  the  greatest  convexity  in  the 
umbonal  region  from  which  the  surface  slopes  rather  gently  to  the  front 
and  lateral  margins ;  without  a  distinct  mesial  fold.  Beak  rather  small, 
not  incurved.  Cardinal  area  moderately  wide,  and  arching  backward  to 
the  point  of  the  beak,  so  that  the  height  of  the  cardinal  area  is  about 
equal  to  its  width.  Dorsal  valve  slightly  convex  or  nearly  plane,  the 
middle  portion  depressed  into  a  shallow,  ill-defined  mesial  sinus,  which 
widens  from  the  beak  to  the  front  margin.  Beak  small,  not  incurved, 
cardinal  area  narrow,  extending  nearly  in  the  plane  of  the  valves.  Sur- 
face of  both  valves  marked  by  moderately  fine,  radiating  striae  which 
bifurcate  near  the  beaks,  and  each  of  these  gives  ofT  a  smaller  branch  a 
short  distance  posterior  to  the  middle  of  the  shell.  In  this  second  branch- 
ing of  the  striae  the  smaller  one  appears  to  be  given  ofT  on  the  outside 
in  the  ventral  valve,  and  on  the  inside  in  the  dorsal.  Concentric  lines 
are  usually  absent. 

The  dimensions  are :  length,  about  8  mm. ;  width,  about  10  mm. ; 
thickness,  2  to  3  mm. 

Shells  of  this  species  are  not  rare  in  the  Girardeau  limestone  in 
Alexander  County,  Illinois. 

Rhynchotremaf  illinoisensis  n.sp. 
(Plate  III,  figures  22  and  23) 
Shells  bear  some  resemblance  to  those  identified  by  Ulrich  and 
Schuchert  as  Rhynchotrema  inacquirahis  from  the  Maquoketa  at  Sa- 
vanna, Illinois.  They  difTer  from  that  form  in  the  smaller  size ;  in  the 
less  elevated  fold  and  more  shallow  sinus;  in  the  erect  (not  incurved) 
beak  of  the  ventral  valve,  and  in  the  less  numerous  concentric  growth  lines 
over  the  surface  of  the  valves.  Shell  small,  subtriangular  in  outline, 
slightly  wider  than  long,  the  greatest  width  anterior  to  the  middle ;  the 
front  margin  straight  or  very  slightly  rounded,  not  extended  in  the  middle 
portion.  Ventral  valve  convex  in  the  umbonal  region  becoming  flattened 
a  little  behind  the  middle,  where  it  gradually  becomes  depressed  into  a 
mesial  sinus  which  broadens  and  deepens  anteriorly,  and  is  occupied  by 
three  plications.  Beak  much  elevated,  acute,  not  incurved.  Dorsal  valve 
broadly  triangular,  convex,  the  median  area  slightly  depressed  in  the  um- 
bonal region,  but  in  the  anterior  half  of  the  shell  it  becomes  elevated  into 
a  low  fold  which  bears  four  subequal  plications.  Beak  strongly  incurved 
beneath  that  of  the  ventral  valve.     Surface  of  dorsal  valve  marked  by 


104  BIENNIAL   REPORT 

14  subangular  plications,  of  which  4  are  slightly  elevated  into  a  fold  near 
the  front  margin.  Ventral  valve  bearing  15  plications,  of  which  3  are 
depressed  into  a  shallow  sinus.  Around  the  margins  the  extensions  of 
the  grooves  on  one  valve  fit  into  corresponding  angular  notches  below 
the  ribs  of  the  opposite  valve.  A  few  concentric  lines  are  present  near 
the  margins  of  both  valves. 

The  dimensions  are:  length,  9  to  10  mm.;  width,  10  to  11  mm.; 
thickness,  4.5  mm. 

In  some  features  this  species  resembles  Rhynchonella?  janea  of  the 
Edgewood  formation,  from  which  it  differs  in  its  smaller  size,  in  its 
lower  and  less  angular  plications,  and  in  the  less  incurved  beak  of  the 
ventral  valve.  The  species  is  not  rare  in  the  Girardeau  limestone,  near 
Thebes,  Illinois. 

Camarotoechiaf  fcstinata  n.sp. 
(Plate  III,  figures  24,  25  and  26) 

Shells  resemble  small  individuals  of  Camarotoechiaf  scobina,  from 
the  Brassfield  of  Ohio,  in  their  triangular  outline ;  strong  angular  plica- 
tions ;  and  in  having  the  two  exterior  plications  of  the  fold  narrower  and 
less  elevated  than  the  inner  ones.  It  differs  from  that  species  in  its 
smooth  (non-granular)  surface;  in  its  smaller  size;  in  the  lower  eleva- 
tion of  the  fold  and  the  shallower  sinus  at  the  front  margin ;  and  in  having 
one  less  plication  on  either  side  of  the  fold  and  sinus. 

Shell  small,  triangular  to  subquadrate  in  outline,  width  and  length 
about  equal,  the  valves  sub-equally  convex.  Ventral  valve  with  acumin- 
ate but  not  strongly  incurved  beak;  greatest  convexity  in  the  umbonal 
region  from  which  the  slope  is  gradual  towards  the  front  and  lateral  mar- 
gins ;  a  sinus  begins  near  the  middle,  becoming  wider  and  deeper  towards 
the  front  where  it  is  somewhat  prolonged  to  fill  the  notch  formed  by 
the  elevation  of  the  fold  in  the  dorsal  valve.  Dorsal  valve  the  more 
convex,  the  convexity  greatest  in  the  median  area  which  is  elevated  into 
a  fold  bearing  four  plications,  of  which  the  two  middle  ones  are  much 
stronger  and  more  elevated  than  the  outer.  Beak  strongly  incurved 
beneath  that  of  the  ventral  valve.  Surface  of  both  valves  having  about 
four  plications  on  either  side  of  the  fold  and  sinus,  and  marked  with  a 
few  fine  concentric  lines  over  the  anterior  one-third  of  the  shell. 

The  average  dimensions  are:  length,  about  12  mm.;  width,  11  mm.; 
thickness,  6  mm. 

This  species  is  not  rare  in  the  Girardeau  limestone  near  Thebes, 
Illinois. 


ALEXANDRIAN  SERIES  105 

Homoeospira  immatura  n.sp. 

(Plate  III,  figures  16,  17  and  18) 

Shell  is  small,  ovate,  the  valves  moderately  and  sub-equally  convex. 
The  ventral  valve  more  convex  than  the  dorsal,  the  greatest  convexity 
immediately  in  front  of  the  umbo,  highest  along  the  median  line  where 
the  furrow  between  the  radial  striae  on  either  side  of  the  middle  is  double 
the  width  of,  and  decidedly  deeper  than,  the  ordinary  furrows.  Beak 
small,  acute,  incurved  over  the  hinge.  Dorsal  valve  slightly  flattened 
along  the  middle  line  posteriorly,  but  becoming  uniformly  slightly  convex 
toward  the  front  margin.  The  middle  stria  is  larger  than  those  on  either 
side. 

The  surface  of  both  valves  bearing  9  or  10  rather  strong  striae  on 
either  side  of  the  median  line.  Along  the  margins  the  furrows  of  the 
ventral  valve  end  in  angular  extensions  which  fit  into  notches  below  the 
ridges  of  the  dorsal  valve,  forming  a  zig-zag  line. 

The  dimensions  are :  length,  6  to  9  mm. ;  width,  4  to  6.5  mm. ; 
thickness,  2.5  mm. 

This  species  occurs  in  the  Girardeau  limestone,  near  Thebes,  Illinois, 
where  it  is  associated  with  Cornulites  incurvus  and  other  common  Gir- 
ardeau forms.  It  differs  from  Homoeospira  apriniformis  Hall  in  its 
smaller  size,  more  oblong  shape,  and  the  fewer  and  more  angular  plica- 
tions. From  H.  pisum  Foerste  it  may  be  distinguished  by  its  narrower 
width,  the  less  distinct  median  grooves  in  which  there  are  no  plications  on 
either  valve,  and  the  fewer  radiating  ridges.  The  characters  in  which 
our  species  differs  from  H.  pisum  Foerste  also  serve  to  distinguish  it 
from  II.  beecheri  Foerste,  which  it  resembles  in  its  small  size. 

Protozeuga  sulcocarinata  n.sp. 
(Plate  III,  figures  19,  20  and  21) 
Shell  is  small,  biconvex,  ovoid  or  subelliptical  in  outline,  longer  than 
wide ;  the  greatest  width  near  the  middle,  tapering  to  the  beaks,  the 
anterior  margin  truncate.  Ventral  valve  strongly  convex  in  the  median 
portion,  from  which  the  slope  is  rather  abrupt  to  the  sides  which  appear 
slightly  flattened  near  the  lateral  margins.  A  furrow  begins  in  the 
median  line  near  the  middle  of  the  shell,  which  deepens  and  widens  to 
the  front,  and  appears  to  be  bordered  on  either  side  by  a  ridge.  In  some 
of  the  exfoliated  shells  is  a  furrow  bordering  either  side  of  the  median 
area  of  greatest  convexity,  beginning  on  either  side  of  the  beak  and 
reaching  the  lateral  margins  a  short  distance  anterior  to  the  middle ;  these 
furrows  are  only  faintly  perceptible  in  specimens  in  which  the  shells  are 
entire.  Beak  prominent,  elevated,  but  not  strongly  incurved  over  the 
dorsal  valve ;  bearing  a  foramen.     Dorsal  valve  slightly  less  convex  than 


106  BIENNIAL  REPORT 

the  ventral,  the  convexity  greatest  a  short  distance  posterior  to  the 
middle,  sloping  rather  evenly  to  the  margins.  On  the  anterior  half  of  the 
valve  there  is  a  median  elevation,  bordered  on  either  side  by  a  furrow, 
which  at  the  front  margin,  indents  the  opposing  ridges  in  the  ventral  valve, 
forming  a  slightly  zig-zag  line  of  junction  of  the  valves  along  the  trun- 
cated anterior  portion  of  the  shell ;  except  the  furrow  bordered  on  either 
side  by  a  ridge  in  the  median  anterior  portion  of  the  ventral  valve,  and 
the  elevation  bordered  on  each  side  by  a  furrow  in  the  anterior  portion 
of  the  dorsal  valve,  the  surface  shows  no  radiating  or  concentric  mark- 
ings. 

The  dimensions  are :  length,  4  mm. ;  width,  2.25  mm. ;  thickness, 
1.25  mm. 

In  shape  and  size,  the  shells  of  this  species  resemble  those  of  Wald- 
heimia  bicarinata,  described  by  Davidson  in  Vol.  36  of  the  Paleontograph- 
ical  Society,  Silurian  supplement,  p.  76,  Plate  IV,  figures  1  to  3,  from 
the  upper  Wenlock  shales.  They  differ  from  the  British  species  in  having 
a  larger  apical  angle,  in  the  wider  posterior  portion  of  the  shell,  in  the 
relatively  greater  convexity  of  the  dorsal  valve,  in  the  stronger  sulcus 
dividing  the  median  ridge  in  the  anterior  half  of  the  ventral  valve,  and  in 
the  stronger  ridge  and  bordering  furrows  that  occupy  the  median  depres- 
sion in  the  anterior  portion  of  the  dorsal  valve. 

The  shells  are  abundant  in  the  Girardeau  limestone  near  Thebes,  Illi- 
nois. They  also  occur  in  the  Noix  oolite  member  of  the  Edgewood  lime- 
stone at  Louisiana,  Missouri. 

Mollusca 
Pelecypoda 

Pterinea  formosa  n.sp. 
(Plate  IV,  figure  1) 
In  some  respects  this  species  resembles  Pterinea  brisa  Hall  from 
which  it  differs  in  the  less  strongly  marked  anterior  auriculation,  in  the 
narrower  postero-basal  portion,  and  in  the  fewer  and  less  distinct  radiat- 
ing striae,  and  the  less  conspicuous  concentric  markings.  In  our  shell 
the  left  valve  is  oblique,  longer  than  high,  greatest  length  along  the 
cardinal  line,  moderately  convex  in  the  umbonal  region,  sloping  more 
gently  near  the  margins,  ovate  in  outline,  exclusive  of  the  auriculations. 
Beak  situated  about  one-third  of  the  length  of  the  cardinal  margin  from 
the  anterior  extremity,  cardinal  margin  bordered  behind  by  an  obscure 
marginal  ridge,  the  posterior  auriculation  depressed  convex,  rather 
sharply  defined  from  the  body  of  the  shell,  sinuate  posteriorly,  extended 
at  the  postero-cardinal  extremity  into  an  acute  point.  Anterior  auricu- 
lation short,  not  much  flattened  and  not  sharply  defined  from  the  body 


ALEXANDRIAN  SERIES  107 

of  the  shell,  forming  an  acute  angle  with  the  antero-cardinal  line,  blend- 
ing with  a  broad  curve  into  the  basal  margin  which  is  rounded  to  the 
posterior  body  portion,  becoming  concave  along  the  margin  of  the  pos- 
terior wing.  Surface  marked  by  low,  rounded  radiating  striae  which 
are  confined  to  the  body  portion  of  the  shell.  Entire  surface  covered  with 
rather  uniform  concentric  lines  of  growth  which  are  most  conspicuous 
over  the  auriculations. 

The  dimensions  are :  length,  20  mm. ;  height,  16  mm. ;  convexity, 
3.5  mm. 

Shells  of  this  species  are  not  rare  in  the  Girardeau  limestone  in 
Alexander  County,  Illinois. 

Modiolopsis  concinna  n.sp. 
(Plate  IV,  figure  2) 

Shells  resemble  those  of  Modiolopsis  faba  (Conrad)  in  general  out- 
line and  in  the  oblique  sinus  on  the  anterior  portion  of  the  shell,  but  dif- 
fering from  that  species  in  the  shorter  extension  of  the  shell  anteriorly, 
and  in  the  less  prominent  sinus.  They  are  subrhomboidal  to  subquadrate 
in  outline,  moderately  convex,  the  greatest  convexity  a  little  above  the 
middle,  length  nearly  twice  the  height,  hinge  about  two-thirds  the  greatest 
length,  beaks  not  much  elevated,  depressed  and  very  strongly  incurved, 
situated  near  the  anterior  margin.  Anterior  end  narrower  than  the 
posterior,  short  and  rounded  to  the  ventral  portion  which  is  straight  or 
very  slightly  convex,  faintly  indented  a  little  anterior  to  the  middle  by 
the  shallow  sinus  which  extends  from  the  beaks  obliquely  over  the  flat- 
tened umbones  to  the  ventral  margin ;  the  posterior  end  broadly  rounded, 
a  narrow  border  along  the  cardinal  margin  slightly  flattened  and  expanded 
in  the  posterior  portion,  the  valves  most  prominent  between  the  flattened 
postero-cardinal  portion  and  the  sinus.  Surface  marked  by  numerous 
fine  and  coarser  concentric  lines. 

The  dimensions  are :  length,  7.5  to  9.5  mm. ;  height,  3.5  to  5  mm. ; 
thickness,  3  to  4  mm. 

This  species  is  not  rare  in  the  Girardeau  limestone  near  Thebes, 
Illinois. 

Gastropoda 

Conradella  sp. 

(Plate  IV,  figure  5) 

Fragments  of  a  species  of  Conradella  which  seems  to  be  related  to, 
if  not  identical  with,  C.  dyeri  Hall  are  not  rare  in  the  Girardeau  lime- 
stone. They  also  somewhat  resemble  C.  imbricata  Meek  and  Worthen, 
but  none  of  them  are  sufficiently  perfect  for  satisfactory  specific  identi- 
fication. 


108  BIENNIAL  REPORT 

cf.  Cyclonema  canccllata  Hall 

(Plate  IV,  figure  4) 

1843.     Littorina  canccllata.     Hall,  Geology  New  York;  Rept.  Fourth  District,  p.  72, 

figures  5,  6. 
1851.  Cyclonema  canccllata.  Hall.  Pal.  New  York,  vol.  2,  p.  90,  pi.  28.  fig- 
ures la-lg. 
Hall's  description :  "Obliquely  sub-conical  or  globose,  with  a  short  spire ; 
volutions  about  four,  rounded,  rapidly  increasing  from  the  apex  so  that  the  last 
one  occupies  almost  the  entire  bulk  of  the  shell ;  aperture  scarcely  expanded ;  sur- 
face marked  by  prominent  thread-like  lines,  coincident  with  the  spire,  which  are 
decussated   by   finer  elevated   striae   in   a   slightly  oblique   direction. 

"In  young  shells,  the  decussating  striae  are  usually  well  preserved,  while 
they  gradually  become  obsolete  in  older  specimens,  which  are  likewise  frequently 
distorted  by  pressure. 

The  specimens  from  the  Girardeau  limestone  are  not  usually  in  a 
perfect  state  of  preservation,  but  they  are  referred  provisionally  to  the 
above  species. 

Diaphorostoma  niagarensis  var.  immatura  n.var. 
(Plate  IV,  figure  3) 

This  form  differs  from  the  very  variable  species  Diaphorostoma 
niagarensis  Hall,  which  was  probably  derived  from  it,  in  its  uniformly 
smaller  size,  and  in  the  fewer  (usually  two)  volutions,  in  the  less  ven- 
tricose  body  whorl  and  the  apparent  absence  of  the  spiral  markings. 
Spire  depressed,  rising  about  one-fourth  of  the  height  of  the  shell  above 
the  plane  of  the  outer  volution,  the  latter  not  distinctly  inflated  toward 
the  aperture.  The  average  height  is  about  5  to  7  millimeters,  and  the 
width  about  7  to  10  millimeters.  Apex  small,  expanding  rather  gradually 
to  the  outer  volution  which  enlarges  more  rapidly,  and  is  nearly  circular  in 
cross  section,  except  for  a  short  distance  from  the  aperture  where  in 
some  shells  it  is  flattened  or  slightly  furrowed  above  near  the  moderately 
deep  suture.  Surface  marked  by  rather  coarse,  undulating  lines  of 
growth,  but  without  visible  spiral  striae. 

These  shells  differ  from  those  of  D.  niagarensis  var.  trigonostoma 
Meek  of  the  Niagaran  in  their  smaller  size,  in  being  less  depressed,  in 
having  the  periphery  rounded  instead  of  angular,  and  the  volutions  nearly 
circular  instead  of  sub-triangular  in  cross  section. 

They  are  not  rare  in  the  Girardeau  limestone  near  Thebes,  Illinois. 

Arthropoda 
Trilobita 

Proetus  princeps  n.sp. 
(Plate  IV,  figure  14) 
In  a  general  way  the  glabella  of  this  species  resembles  that  of  P. 
determinants  Foerste,  of  the  overlying  Edgewood  formation,  but  differs 


ALEXANDRIAN  SERIES  109 

from  that  species  in  the  more  gently  tapering  anterior  portion  and  in  the 
more  strongly  impressed  lateral  glabellar  furrows  which  extend  inward 
and  backward  in  a  more  oblique  direction  than  in  the  Edgewood  species. 

The  glabella  is  semi-elliptical  in  outline,  depressed  convex,  defined 
by  distinct  dorsal  furrows.  Occipital  segment  faintly  striate  in  a  direc- 
tion parallel  with  the  occipital  furrow,  the  latter  well  defined,  bearing  a 
low  ridge  with  a  lower  narrow  elevation  anterior  to  it,  and  separated  from 
it  by  a  shallow  depression.  A  pair  of  small  subovate  occipital  lobes  are 
situated  behind  the  posterior  lateral  angles  of  the  glabella ;  the  postero- 
lateral glabellar  furrows  not  deeply  impressed,  beginning  at  the  dorsal 
furrows  nearly  opposite  the  eyes  and  extending  very  obliquely  inward 
and  backward  for  three-fourths  of  the  distance  to  the  occipital  furrow ; 
the  second  lateral  glabellar  furrows  faint,  oblique,  originating  about  one- 
third  of  the  length  of  the  glabella  from  its  anterior  portion,  and  continuing 
about  one-half  the  distance  across  either  side  of  the  glabella ;  the  first 
lateral  glabellar  furrows  obsolete.  The  anterior  extremity  of  the  glabella 
is  separated  from  the  marginal  border  by  a  narrow  band,  fixed  cheeks 
very  narrow,  the  palpebral  lobes  rising  directly  from  the  dorsal  furrows. 

The  dimensions  of  a  cranidium  are :     length,  7.5  mm. ;  width,  6  mm. 

Shumard26  mentioned  a  species  of  Proetus  associated  with  Cyphaspis 
girardcaucnsis  and  Encrinurus  deltoideus  in  the  Girardeau  limestone,  as 
Proetus  depressus,  but  published  no  figure  or  description  of  this  species. 
In  1902  Weller27  described  a  species  of  Proetus?  from  the  Decker  Ferry 
formation  (Silurian)  of  New  Jersey  under  the  name  of  Proetus  de- 
pressus, so  that  this  name  cannot  be  applied  to  the  species  of  Proetus 
from  the  Girardeau  limestone.  Fragments  of  this  trilobite  are  not  rare 
in  the  Girardeau  limestone  near  Thebes,  Illinois. 

Cyphaspis  girardeaueusis  Shumard 
(Plate  IV,  figure  13) 

1855.  Cyphaspis  girardcaucnsis.  Shumard.  Ann.  Repts.  Mo.  Geol.  Survey,  1  and  2, 
p.  197,  pi.  B,  figures  11a,  lib. 
Shumard's  description :  "Body  ovate,  depressed ;  head  nearly  semicircular, 
forming  more  than  one-third  the  length  of  the  body,  very  moderately  convex,  ex- 
terior border  raised,  narrow,  prolonged  posteriorly  into  slender,  arched  spines, 
which  extend  to  the  seventh  thoracic  articulation ;  within  the  border  is  a  narrow 
well-defined  groove,  and  between  this  and  the  furrow  which  passes  round  the  front 
of  the  glabella  is  a  slightly  raised  surface.  Glabella  subovate,  rounded  before, 
truncated  behind,  occupying  rather  more  than  two-thirds  the  length  of  the  head, 
greatest  width  a  little  in  advance  of  the  middle,  surface  moderately  convex  and 
but  little  elevated  above  the  cheeks,  when  compared  with  other  species  of  the 
genus;  at  the  base  on  either  side  is  a  small  ovate  lobe,  about  half  the  length  of 


2,;Schumard,   B.   F.,   Geol.   Survey  of  Mo.   part  2,  n.    198,   1855. 

2TWeller,    Stuart,    N.   J.    Geol.    Survey,    Paleontology,    vol.    3,    p.    249,    1902. 


110  BIENNIAL   REPORT 

the  glabella,  and  entirely  separated  from  it  by  a  narrow,  deeply  impressed  groove  ; 
longitudinal  furrows  narrow,  profound,  uniting  in  front  of  the  glabella;  occipital 
furrow  straight,  narrow,  deep  ;  occipital  ring  about  as  high  as  the  glabella,  wide  in 
the  middle,  narrowing  towards  the  extremities,  garnished  with  a  minute  central 
granule ;  cheeks  depressed  convex ;  eyes  small,  nearly  circular,  situated  very  near 
the  glabella,  and  opposite  the  anterior  half  of  its  lateral  lobes.  Thorax  with  ten 
segments,  trilobation  strongly  marked  by  the  longitudinal  furrows ;  axial  lobe 
wider  than  the  lateral  lobes,  slightly  flattened  in  the  middle,  rings  slightly  arched 
towards  the  front,  separated  by  strong  furrows ;  seventh  ring  provided  with  a 
slender  spine,  a  little  flattened  on  the  sides  ;  it  extends  directly  backwards,  nearly 
two  lines  beyond  the  extremity  of  the  pygidium.  The  entire  length  of  this  ap- 
pendage is  about  four  lines;  it  rises  by  a  thickened  base,  and  terminates  in  an  acute 
point.  Pleurae  rounded  at  extremities,  each  with  a  deep  groove  running  nearly 
the  entire  length,  bend  of  the  knee  nearest  the  axial  extremities.  Pygidium  semi- 
circular, twice  as  wide  as  long,  border  narrow,  axial  lobe  about  as  wide  as  one 
lateral  lobe,  rings  from  five  to  eight  (varying  in  different  specimens)  segments  of 
lateral  lobes  tolerably  distinct,  grooved  throughout  their  entire  length.  The  sur- 
face of  the  crust  appears  perfectly  smooth  to  the  naked  eye,  but  when  examined 
with  a  strong  lens,  numerous  minute  granulae  are  to  be  seen.  Length,  7  lines ; 
greatest  breadth,   6  lines;   length  of  head,   2Yi   lines. 

"Formation  and  Locality:  It  occurs  in  the  Upper  Silurian  strata  (Cape 
Girardeau  limestone),  on  the  Mississippi  River,  two  miles  above  Cape  Girardeau, 
Missouri,  where  it  is  associated  with  Proetus  depressus,  Encrinurus  deltoideus  and 
Homocrinus." 

Imperfect  glabellae  of  this  species  are  rather  common  in  the  Gir- 
ardeau limestone  of  Illinois,  but  no  specimens  approaching  in  perfection 
the  one  figured  by  Shumard  were  found. 

Acidaspis  halli  Shumard 
(Plate  IV,  figures  11  and  12) 

1855.  Acidaspis  halli.  Shumard,  Ann.  Repts.  Mo.  Geol.  Survey,  1  and  2,  p.  200, 
pi.  B,  figures  7a-7c. 
Shumard's  description  :  "The  glabella  is  very  moderately  convex ;  its  length 
is  2]4  lines,  and  its  width,  between  the  eyes,  is  about  3  lines  ;  frontal  border  ele- 
vated, garnished  with  a  row  of  closely-set  granules,  and  limited  internally  by  a 
deep  furrow;  dorsal  sinuses  rather  deep  and  nearly  parallel  with  each  other; 
false  sinuses  well  defined  from  their  commencement  at  the  middle  lateral  furrows, 
to  the  occipital  furrow,  mesial  lobe  of  glabella  slightly  elevated  above  the  lateral 
lobes,  and  bearing  a  wide  frontal  lobe,  forming  a  little  more  than  a  fourth  of  its 
length,  and  behind  which  the  sides  are  slightly  arched ;  of  the  lateral  lobes  the 
middle  one  is  nearly  circular,' the  posterior  one  oval;  no  antero-lateral  sinuses,  the 
middle  and  posterior  ones  neatly  defined  and  deep ;  occipital  sinus  distinctly  marked, 
but  rather  shallow  in  its  middle  third  ;  occipital  ring  very  slightly  elevated  above 
the  plane  of  the  median  lobe,  rather  wide  in  the  middle,  constricted  at  the  ex- 
tremities, posterior  edge  of  constricted  portion  bearing  a  prominent  granule  on 
either  side;  area  between  the  groove  of  the  ocular  thread  and  dorsal  sinus  nar- 
row, triangular,  and  ornamented  with  a  double  row  of  granules ;  ocular  thread 
very   slender,  bearing  a   single   series  of  granules;   eyes   situated   directly  opposite 


ALEXANDRIAN  SERIES  111 

the  posterior  lateral  lobes ;  movable  cheeks  as  wide  as  the  median  lobe  of  the 
glabella  is  long ;  border  well  defined,  and  terminating  posteriorly  in  a  slightly 
•curved  acute  spine,  about  two  lines  in  length ;  exterior  edge  ornamented  with 
about  fourteen  spines,  increasing  in  length  as  they  recede  from  the  front,  and  two 
of  them  situated  on  the  genal  spine ;  the  forward  ones  are  blunt  at  their  extrem- 
ities, the  others  are  drawn  to  a  sharp  point. 

"Thorax :  The  number  of  segments  composing  the  thorax  is  unknown.  In 
the  specimen  figure,  which  is  the  most  perfect  one  in  our  possession,  eight  are 
preserved ;  axis  not  so  wide  as  one  of  the  lateral  lobes ;  lateral  segments  each 
tearing  a  bourrelet  of  semi-cylindrical  form,  occupying  about  half  its  width,  and 
garnished  with  a  row  of  granules;  posterior  band  very  narrow  and  difficult  to  be 
seen ;  anterior  band  very  slightly  convex,  narrow  and  granulose. 

"Pygidium  minute,  sub-semicircular ;  axial  lobe  occupying  about  one-third 
the  entire  width,  consisting  of  two  rings;  lateral  lobes  very  slightly  convex;  the 
■single  segment  which  arises  from  the  first  axial  ring  is  narrow  at  its  origin,  but 
becomes  rather  broad  before  attaining  the  margin ;  it  is  prolonged  into  a  primary 
spine,  one  on  each  side,  about  one  and  a  half  lines  long,  and  between  these  are 
two  secondary  spines,  about  half  as  long  as  the  former ;  the  lateral  borders  are 
also  furnished  with  two,  and  sometimes  three  secondary  spines  on  either  side. 
Length,  about  7  lines;  width  of  eighth  rib  of  thorax,  exclusive  of  spines,  6% 
lines  ;  length  of  pygidium,  1  line. 

"Formation  and  Locality:  Fragments  of  this  elegant  little  tribolite  are  quite 
common  in  the  Cape  Girardeau  limestone  on  the  Mississippi  River,  in  Cape  Girard- 
eau County." 

Fragments  of  this  trilobite  are  not  rare  in  the  Girardeau  limestone,  in 
Illinois.  Our  specimens  show  eight  segments  in  the  thorax,  as  figured  by 
Shumard. 

Encrimirus  deltoid  ens  Shumard 

(Plate  IV,  figure  10) 

1855.  Encrinurns  deltoideus.  Shumard,  Ann.  Repts.  Mo.  Geol.  Survey,  1  and  2, 
p.   198,  pi.  B,  figure  10. 

Shumard's  description  :     "Head  and  thorax  unknown. 

"Pygidium  subtriangular,  width  greater  than  the  length,  moderately  convex, 
arched  before,  extremity  rounded  and  bent  slightly  upward ;  axial  lobe  flattened 
•convex,  a  little  elevated  above  the  convexity  of  the  lateral  lobes,  from  which  it  is 
well  defined  by  the  longitudinal  furrows ;  rings  about  twenty-four,  narrow ;  the 
first  four  or  five  only  are  entire,  the  others  are  interrupted  by  a  longitudinal  space, 
■which  runs  down  the  middle  of  the  axis,  and  bears  several  very  small  granules, 
which  are  indistinct,  and  in  the  specimens  before  us,  are  only  apparent  on  the 
anterior  third  of  its  length  ;  on  each  side  of  this  interval,  the  rings  are  separated 
ty  strong  transverse  furrows,  nearly  as  wide  as  the  rings,  lateral  lobes  each  about 
one  and  a  half  times  the  width  of  axial  lobe ;  ribs  eight  on  each  side,  narrow  at 
their  origin,  and  becoming  wider  as  they  approach  the  border,  curved  downward 
and  backwards,  the  last  two  or  three  being  nearly  parallel  with  a  line  drawn  through 
the  length  of  the  axis ;  furrows  deep,  smooth,  and  about  half  as  wide  as  the  ribs. 
The  surface  of  the  test  appears  perfectly  smooth  to  the  unassisted  eye,  excepting 


112  BIENNIAL   REPORT 

the  annulations  of  the  axis,  which  show  traces  of  granules.     With  the  magnifier, 

minute  granulae  are  to  be  seen,  particularly  near  the  borders  and  posterior  extremity. 

"The  dimensions  of  the  largest  pygidium  are  :  length,  9  lines ;  width  10^4  lines." 

Pygidia  and  fragments  of  the  cephalon  of  this  species  are  not  rare 

in  the  Girardeau  limestone  in  the  vicinity  of  Thebes,  Illinois. 

Calymene  dubia  n.sp. 
(Plate  IV,  figures  8  and  9) 

Glabella  convex,  well  defined  by  the  dorsal  furrows,  subquadrilateral 
in  outline,  tapering  anteriorly ;  anterior  end  truncate,  about  4.5  mm.  wide, 
while  the  posterior  end  is  about  7.5  mm.  wide;  length  about  equal  to  the 
width  at  the  posterior  end.  Lateral  glabellar  furrows  not  extending 
across  the  middle  portion  of  the  glabella,  the  first  pair  short  and  faint, 
inclined  slightly  downward,  originating  in  the  dorsal  furrows  about  1.75 
mm.  below  the  anterior  end,  and  distinguishable  for  a  distance  of  about 
2  mm.,  second  pair  deeper  and  longer  than  the  first,  nearly  transverse  in 
direction,  originating  1.25  mm.  below  the  first  pair  and  distinct  for  a  length 
of  2.5  mm. ;  posterior  pair  a  little  stronger  than  the  second,  with  a  slight 
sigmoid  downward  curve,  about  3.25  mm.  long,  originating  about  1.5 
mm.  below  the  second  pair,  and  2.5  mm.  in  front  of  the  occipital  furrow ; 
a  faint  trace  of  bifurcation  appears  at  their  inner  extremities.  Occipital 
furrow  narrow,  distinct,  arching  slightly  forward  in  the  middle  portion 
where  it  is  shallowest.  The  dorsal  furrow  showing  a  slight  depression 
a  short  distance  anterior  to  the  point  of  origin  of  the  first  lateral  glabellar 
furrows.     Entire  surface  covered  with  minute  tubercles  of  different  sizes. 

Pygidium  subtriangular  in  outline,  without  marginal  border,  axial 
lobe  bounded  by  poorly  defined  dorsal  furrows,  tapering  posteriorly  to 
an  obtusely  rounded  extremity  which  terminates  within  the  marginal 
border,  marked  by  about  seven  low  annulations,  of  which  the  posterior 
ones  are  faintly  defined.  Pleural  lobes  with  the  anterior  lateral  angles 
flattened,  sloping  quite  strongly  from  the  dorsal  furrows  to  the  lateral 
margins,  having  five  segments  which  show  no  longitudinal  depressions, 
the  furrows  that  separate  the  segments  fading  out  a  short  distance  before 
reaching  the  lateral  margins.  Surface  of  glabella  and  pygidium  covered 
with  small  irregularly  disposed  tubercles  of  different  sizes. 

The  dimensions  of  the  pygidium  are :  length,  9  mm. ;  greatest 
width,  12  mm. 

This  species  resembles  Calymene  platycephala  Foerste  from  the 
Saltillo  limestone  at  Clifton,  Tennessee,  in  the  flat  character  of  the 
glabella  and  the  shallow  glabellar  furrows,  but  differs  from  it  in  being- 
much  smaller  in  size,  in  having  the  glabellar  furrows  much  less  distinct, 
and  the  posterior  pair  much  less  strongly  curved.  Fragments  of  this 
species  are  common  in  the  Girardeau  limestone  in  Alexander  County, 
Illinois. 


alexandrian  series  113 

Descriptions  of  Species  from  the  Edgewood  Formation 

Coelenterata 

Anthozoa 

Zaphr cutis  subregularis  n.sp. 

(Plate  V,  figure  5,  and  Plate   IX,  figure   1) 

Corallum  simple,  turbinate,  nearly  straight,  expanding  from  the  acute 
base  so  that  the  top  of  the  calyx  often  has  a  diameter  of  V/%  inches  when 
the  length  of  the  corallum  is  ll/>  inches;  surface  irregularly  annulated  by 
low  transverse  ridges  of  various  sizes,  in  well  preserved  specimens  numer- 
ous fine  transverse  striae  are  present,  of  which  10  or  12  occur  in  a  distance 
of  1  millimeter,  longitudinal  or  septal  striae  usually  distinct.  Calyx  mod- 
erately deep,  with  thin  walls.  Septa  alternately  long  and  short,  the 
latter  but  slightly  developed,  the  former  generally  curved,  about  36  to 
44  in  a  calyx  1  inch  in  diameter,  continuous  vertically  in  the  peripheral 
portion,  but  the  continuity  in  the  central  portion  broken  by  the  tabulae, 
distinct  for  a  distance  of  one-fourth  to  three-eighths  of  an  inch,  their 
inner  ends  often  coalesced  in  sets  of  two  or  three  towards  the  center, 
towards  the  top  there  is  considerable  space  in  the  central  portion  that  is 
occupied  only  by  the  tabulae  which  are  close  set  and  somewhat  undulating, 
some  of  them  incomplete  or  inosculating,  concave  in  the  middle  portion 
and  bent  downward  at  the  periphery. 

In  external  appearance  this  species  resembles  the  figures  of  Strep- 
telasmaf  geometricum  Foerste,  but  in  our  form  there  is  no  pseudoco- 
lumella  formed  by  the  twisting  together  of  the  inner  edges  of  the  primary 
septa  at  the  center,  as  in  the  genus  Streptelasma.  Foerste's  description 
is  too  meagre  to  permit  a  satisfactory  comparison  to  be  made  with  that 
species.  This  coral  is  common  in  the  Edgewood  limestone  in  Pike  County, 
Missouri,  and  coralla  thought  to  represent  the  same  species  are  also 
common  in  the  Channahon  limestone  in  Will  County,  Illinois. 

Zaphrentis  cf.  stokcsi.     Milne-Edwards  and  Haime 
(Plate  V,  figure  4) 

1851.  Zaphrentis    stokesi.      Milne-Edwards    and    Haime,    Polyp.    Foss.    des    Terr. 

Palaeoz.,  p.  330,  pi.  3,  figure  9. 

1852.  fCanina  bilateralis,   Hall,  Pal.  New  York,  vol.  2,  p.  41,  pi.  17,  figures  3a-3h, 

and  p.  113,  pi.  32,  figures  3a-3c. 
1852.     fPolydilasma  turbinatum.     Hall,  Ibid,  p.  112,  pi.  32,  figure  2. 
1866.     Zaphrentis  stokesi.     Billings,  Cat.  Sil.  Foss.  of  Anticosti,  p.  34. 

1875.  Zaphrentis  stokesi.     Nicholson,  Paleontology  Ontario,  pp.  43  and  58. 

1876.  Zaphrentis  stokesi.     Rominger,    Fossil    Corals,    Mich.    Geol.    Survey,    p.    145, 

pi.  51,  three  figures  in  lower  row. 
1901.     Zaphrentis  stokesi.     Lambe,    Contrib.    to    Can.    Paleontology,    vol.    4,    pt.    2, 
p.  120,  pi.  9,  figures  1,  la  and  2. 


114  BIENNIAL  REPORT 

Rominger's  description  :  "Symmetrically  curved  conical  polyparia,  sometimes 
elliptical  in  outline  by  a  compression  in  a  direction  transverse  to  the  curvature. 
Length  of  cones  about  twice  the  diameter  of  the  calyces,  which  in  middle-sized 
specimens  is  about  four  centimeters.  Calyces  moderately  deep  with  erect  margins 
and  a  spacious  subconvex  bottom,  on  which  the  lamellae  unite  in  an  irregularly 
twisted,  interlacing  manner  as  low  carinae.  Lamellae  linear,  stout ;  sixty  to  sixty- 
five  larger  ones  alternating  with  as  many  small  rudimentary  crests  may  be  counted 
in  the  circumference  of  calyces  four  centimeters  wide.  A  large  septal  fovea  is 
situated  in  the  median  line  of  the  convex  side  of  the  curved  polyparia.  Trans- 
verse diaphragms  well  developed ;  the  crests  on  the  upper  side  do  not  connect 
into  continuous  vertical  leaves  with  those  of  the  succumbent  cups ;  the  lower  side 
of  the  diaphragms  is  generally  smooth,  not  crested.  The  external  walls  of  the 
specimens  are  rarely  preserved  in  the  silicified  condition,  and  the  excoriated  sur- 
face is  longitudinally  ribbed  by  the  exposed  vertical  plications.  In  some  speci- 
mens, however,  the  superficial  epithecal  crust  is  perfectly  preserved." 

Coralla  resembling  those  of  this  species  were  found  in  the  Edgewood 
formation  in  Alexander  County,  Illinois,  and  Pike  County,  Missouri. 

Zaphrentis  ambigua  n.sp. 

(Plate  IX,  figure  2) 

For  the  description  of  this  species  refer  to  descriptions  of  the  fossils 
of  the  Channahon  limestone  member  of  the  Edgewood  formation. 

Coralla  thought  to  belong  to  this  species  are  common  in  the  Edge- 
wood  limestone  near  Edgewood,  and  in  the  Noix  oolite  member  of  the 
formation  at  Louisiana  and  south  of  Clarksville,  Missouri. 

Favosites  subelongus  n.sp. 
(Plate  V,  figures  9  and  10) 

Coralla  growing  in  elongate  club-shaped  masses,  4  or  5  inches  in 
height,  the  height  greater  than  the  width,  with  long  prismatic  corallites 
which  are  of  very  different  sizes  in  the  same  specimen,  the  larger  ones 
having  a  width  of  1.5  to  2  mm.,  and  the  smaller  ones  less  than  one-half 
that  width ;  no  septal  spines  or  ridges  visible.  The  tabulae  are  strong, 
complete,  and  usually  horizontal  or  slightly  oblique,  five  to  ten  in  a  dis- 
tance of  10  mm.  Mural  pores  very  few,  usually  situated  near  or  in  the 
angles  of  the  corallites.     Epitheca  not  seen. 

In  some  characters  this  coral  resembles  Favosites  aspera  d'Orbigny. 
but  may  be  distinguished  from  that  species  by  its  less  expanded  mode  of 
growth,  by  the  smaller  corallites  of  different  diameters  in  the  same  coral- 
lit  m,  by  the  stronger,  and  more  distinct,  complete  tabulae,  and  by  the 
absence  of  septal  spines. 

This  species  occurs  in  the  Edgewood  limestone,  a  short  distance 
below  the  Bowling  Green  member,  near  Edgewood,  at  Louisiana,  and 
south  of  Clarksville,  in  Pike  County,  Missouri. 


ALEXANDRIAN  SERIES  115 

Calapoecia  favosiloidea  n.sp. 
(Plate  V,  figures  1,  2,  and  3) 

This  species  is  distinguished  from  the  form  described  by  Billings 
as  Calapoecia  anticostiensis  in  having  the  corallites  in  contact,  and  poly- 
gonal in  cross  section,  and  in  the  much  smaller  pores  which  are  sub- 
circular  in  outline.  It  differs  from  the  forms  known  as  C.  canadensis 
Billings  and  C.  cribriformis  Nicholson  in  the  much  smaller  coralla  and 
smaller  corallites,  more  distant  and  stronger  tabulae,  and  the  very  much 
smaller  pores,  which  are  less  regular  in  arrangement,  and  never  so  large 
as  to  give  the  walls  a  cribriform  appearance. 

The  corallum  is  subglobular  or  irregularly  rounded ;  width  2  to  3 
inches,  and  height  usually  about  equalling  the  width.  Corallites  in  con- 
tact, polygonal  in  cross  section,  1.5  to  2.5  mm.  in  diameter,  diverging 
from  a  basal  point.  Walls  of  corallites  of  moderate  thickness,  their 
inner  surface  having  12  to  24  longitudinal  spiniform  ridges  separated  one 
from  another  by  a  row  of  numerous  small  pores ;  the  spines  are  short  and 
pointed,  2  to  6  between  adjacent  tabulae ;  pores  rather  small,  subcircular, 
disposed  in  somewhat  irregular  longitudinal  and  transverse  rows ;  tabulae 
usually  complete  and  almost  horizontal,  .25  to  2  mm.  apart ;  epitheca  not 
seen. 

In  some  places  this  species  is  common  in  the  Edgewood  limestone, 
a  short  distance  below  the  Bowling  Green  member,  near  Edgewood  and 
Louisiana  and  south  of  Clarksville,  in  Pike  County,  Missouri. 

Calvinia  nov.gen. 

Corallum  compound,  in  irregularly  hemispherical  to  globular  masses, 
3  to  5  inches  or  more  in  diameter,  composed  of  cylindrical  corallites,  2 
to  3  mm.  distant  from  one  another,  which  emerge  at  right  angles  to  the 
surface,  calyx  with  slightly  exserted  margin ;  septa  in  the  form  of  irregu- 
larly spinose  ridges  along  the  interior  of  the  corallites,  extending  about 
one-third  to  one-half  the  distance  to  the  center ;  tabulae  numerous,  hori- 
zontal and  complete,  spaces  between  the  corallites  filled  with  vesicular 
tissue  composed  of  convex  plates,  resting  upon  one  another,  through 
which  occasional  slender,  cylindrical  tubules  extend  parallel  with  the 
corallites ;  tubules  somewhat  undulating,  rather  uniform  in  size,  their 
walls  taking  no  part  in  the  formation  of  the  vesicular  tissue  through  which 
they  pass. 

This  genus  resembles  Lyellia  in  having  true  vesicular  tissue  present 
in  the  spaces  between  the  corallites,  but  differs  from  that  genus  in  that 
the  tissue  in  the  interstitial  spaces  of  Lyellia  is  wholly  vesicular  while  in 
this  genus  there  are  many  slender,  undulating,  cylindrical  tubules  passing 
through  the  vesicular  tissue  in  a  direction  parallel  with  the  corallites. 


116  BIENNIAL  REPORT 

It  differs  from  Plasmopora  in  that  in  the  latter  genus  the  spaces  be- 
tween the  corallites  are  entirely  filled  with  tubules  within  which  convex 
plates  (tabulae)  have  interfered  with  the  regular  development  of  the 
walls,  resulting  in  their  irregularly  zig-zag  mode  of  growth. 

It  is  distinguished  from  Heliolitcs  by  the  fact  that  in  the  latter  genus 
the  spaces  between  the  corallites  are  occupied  entirely  with  numerous 
intimately  united,  polygonal  tubules  having  thin,  regular  walls. 

The  type  of  the  genus  is  Calvinia  edgewoodensis  n.sp  described 
below : 

Calvinia  edgewoodensis  n.sp. 
(Plate  IV,  figures  15,  16,  and  17) 

Corallum  compound,  massive,  subspherical  to  discoid  in  shape,  the 
larger  specimens  5  to  6  inches  in  diameter ;  corallites  circular  in  section, 
subequal  in  size,  about  25  millimeters  in  diameter,  separated  one  from 
another  by  an  average  distance  a  little  less  than  the  diameter  of  the 
tubes,  walls  of  the  corallites  marked  on  the  exterior  and  interior  by  alter- 
nating longitudinal  ridges  and  furrows ;  septa  represented  by  about  12 
low,  interrupted  vertical  ridges  or  striae  of  unequal  size,  which  bear 
short  spinose  projections  at  irregular  intervals.  Tabulae  generally  com- 
plete and  almost  horizontal,  situated  at  unequal  distances,  averaging  about 
5  in  a  distance  of  5  millimeters.  Sometimes  the  adjacent  tabulae  are 
less  than  .5  millimeters  apart  and  at  other  times  they  are  more  than  2 
millimeters.  The  coenenchyma  is  made  up  of  true  vesicular  tissue 
through  which  numerous,  more  or  less  undulating  cylindrical  tubules  ex- 
tend parallel  with  the  corallites,  and  at  irregular  distances,  usually  less 
than  1  millimeter,  apart;  upper  surface  of  corallum  made  granulose  by 
the  upper  ends  of  the  tubules. 

This  species  occurs  in  the  Edgewood  formation  one-fourth  mile 
southeast  of  Gale,  in  Alexander  County,  Illinois. 

Lyellia  thebesensis  Foerste 
(Plate  V,  figures  6  and  7) 
1909.     Lyellia  thebesensis.     Foerste,  Bull.   Sci.  Lab.   Denison  Univ.,  April,   1909,  p. 
95,  pi.  4,  figures  69A,  69B. 
Foerste's  description  :     "Forming  massive  coralla  with  the  walls  of  neighbor- 
ing corallites  almost  in  contact  with  each  other,  leaving  very  small  inter-spaces  for 
the  coenenchyma.     The  tabulae  average  about  8  or  9  in  a  length  of  5  millimeters 
and  the  plates  in  the   intermediate   spaces   are  more  numerous,  but   not  distinctly 
vesicular.     The  diameter  of  the  corallites  is  slightly  more  than  1  millimeter.     The 
walls  of  the  corallites  are  slightly  crenulated,  and  are  slightly  striated  lengthwise 
No  septa  are  visible." 


ALEXANDRIAN  SERIES  117 

In  some  of  our  specimens  of  this  species  the  convex  plates  which 
compose  the  coenenchyma  are  arranged  one  above  another  in  such  regular 
order  that  their  overlapping  edges  form  irregular  zig-zag  lines  which 
extend  in  a  vertical  direction  and  resemble  the  walls  of  the  tubules  in  the 
related  genus  Plasmopora.  This  species  is  common  in  the  upper  part  of 
the  Edgewood  formation,  near  Thebes,  Illinois,  and  in  the  vicinity  of 
Edgewood,  Louisiana  and  Clarksville,  in  Pike  County,  Missouri. 

Hydrozoa 

Stromatoporoidea 

Clathrodictyon  vcsiculosum  Xicholson  and  Murie 

(Plate  V,  figure  8) 

878.     Clathrodictyon  vesiculosa m.     Nicholson  and   Murie,  Jour.   Linn.   Soc.   Zool., 

vol.  14,  p.  220,  pi.  2,  figures  11-13. 
880.     Clathrodictyon   vcsiculosum.     Nicholson    and     Etheridge,     Mon.     Sil.     Foss. 

Girvan,  p.  238,  pi.  19,  figure  2. 
882.     Stromatopora  conccntrica.     Spencer  Bull.  Mus.  Univ.  Missouri,  vol.   1,  No. 
1,  p.  45. 

886.  Stromatopora  minuta.     Rominger,  Proc.  Acad.  Nat.  Sci.,  Philadelphia,  p.  49. 

887.  Clathrodictyon  vcsiculosum.     Nicholson,  Annals.   Nat.   Hist.   ser.  5,  vol.    19, 

p.  1,  figures  1-3. 
892.     Clathrodictyon  vcsiculosum.     Nicholson,  Mon.  Brit.  Stromatoporoids,  p.  147, 

pi.  17,  figures  10-13,  and  pi.  18,  figure  12. 
896.     Clathrodictyon  vcsiculosum.     Whiteaves,  Can.  Rec.  Sci.,  vol.  7,  p.  134. 
908.     Clathrodictyon  vcsiculosum.     Parks,  Univ.   of  Toronto   Studies,   Geol.   Ser., 
No.  5,  p.  14,  pi.  7,  figures  1  and  6  and  pi.  8,  figures  3,  4  and  5. 
Nicholson  and   Etheridge's  description:     "Skeleton  in  the   form  of  cake-like 
expansions,  from  about  an  inch  to  a  foot  in  diameter,  and   from  half  an  inch  to 
two  inches  in  thickness  in  the  center,  but  thinning  out  towards  the  circumference. 
Young  specimens  sometimes  encrusting  foreign  bodies,  but  the  unattached  portions 
of  the  under  surface  being  otherwise  covered  with  a  concentrically  striated  epitheca. 
Upper  surface  irregularly  undulating  and  exfoliating  concentrically  round  the  ele- 
vated points.     Surface  smooth,  not  tuberculated.     Internal  structure  of  exceedingly 
fine  and  close-set  horizontal  or  slightly  undulating  lamina,  of  which  about  twenty 
occupy  the  space  of  one-tenth  of  an  inch   (counting  in  the  interlaminar  spaces  as 
well).     The  horizontal  laminae  are  undulated  and  inflected  at  short  intervals,   so 
as  to  divide  the  interlaminar  spaces  into  a  series  of  minute  lenticular  vesicles  or 
cells  which  often  communicate  laterally  by  imperfection  of  their  boundaries." 

Concerning  the  horizon  of  this  form  in  America  Parks  says :  "This 
species  occurs  at  the  very  base  of  the  Silurian,  in  the  Lower  Niagara, 
Clinton,  and  in  certain  'passage  beds'  between  the  Clinton  and  the 
Medina."  It  is  not  rare  in  the  Edgewood  strata,  in  Alexander  County, 
Illinois,  and  at  almost  all  of  the  fossil  localities  in  Pike  County,  Missouri. 
It  also  occurs  in  the  Sexton  Creek  limestone  in  the  Illinois  basin. 


118  BIENNIAL   REPORT 

Molluscoidea28 

Brachiopoda 

Rafinesquinaf  mesicosta    (Shumard) 

(Plate  III,  figure  10) 

For  synonymy  and  description  of  this  species  see  a  previous  page  of 

this  paper,  under  the  fossils  of  the  Girardeau  limestone. 

Shells  of  this  species  occur  in  the  Edgewood  limestone  near  Thebes, 
Illinois,  and  near  Edgewood  and  at  Louisiana  in  Pike  County,  Missouri. 

Rafinesquinaf  mesicosta  var.  mesistria  n.var 
(Plate  VI,  figure  6) 

Shells  differ  from  those  of  the  normal  species  in  their  somewhat 
larger  size  and  more  elongate  outline,  and  especially  in  the  much  less 
prominent  alternating  character  of  the  striae.  Near  the  margins  of  the 
shells  of  R.  (Brachyprion?)  mesicosta  every  alternate  stria  from  the 
median  costa  is  distinctly  larger  and  longer  than  the  ones  adjacent,  and 
usually  every  fourth  stria  from  the  median  costa  is  much  stronger  than 
the  three  (sometimes  five)  intervening  ones.  In  the  new  variety,  the 
median  costa  of  the  ventral  valve  is  also  more  prominent  than  any  of 
the  others,  and  every  alternate  stria  is  smaller  and  shorter  than  the  adja- 
cent one  on  each  side,  but  the  further  grouping  of  the  striae  with  three 
to  five  weaker  ones  between  any  two  adjacent  much  stronger  ones,  so 
conspicuous  in  the  shells  of  the  species,  is  rarely  present. 

The  dimensions  are:  length,  about  16  mm.;  greatest  width,  about 
18  mm. 

The  shells  of  this  variety  are  not  rare  in  the  oolite  member  of  the 
Edgewood  limestone  at  Louisiana,  and  near  the  mouth  of  Buffalo  Creek, 
in  Pike  County,  Missouri ;  and  below  Hamburg  in  Calhoun  County,  Illi- 
nois. 

Brachyprion  latisculptilis  n.sp. 
(Plate  VI,  figure  5) 
This  species  resembles  Rafinesquina  (Brachyprion?)  mesicosta 
(Shumard)  in  general  outline,  and  in  having  the  median  costa  of  the 
ventral  valve  more  prominent  than  those  on  the  sides.  It  differs  from 
Shumard 's  species  in  having  only  about  one-half  as  many  striae,  in  the 
much  less  conspicuous  alternating  character  of  the  striae,  and  in  having* 
the  median  costa  of  the  ventral  valve  relatively  much  less  prominent.     It 


28A  number  of  poorly  preserved  bryozoa  were  collected  from  the  Edgewood  strata  near 
Thebes,  Illinois,  and  at  Louisiana,  Missouri.  These  were  submitted  to  Dr.  E.  R.  Cummings- 
for  study,  who  has  furnished  the  following  preliminary  statement  concerning  them:  "None 
of  your  bryozoa  are  identical  with  described  species.  They  appear  to  belong  to  the  genera 
Lioclema,  Orbignyclla,  Diamcsopora,  and  Monotrypa.  If  you  have  other  evidence  that  these 
came  from  Silurian  rocks  older  than  early  Niagaran,  the  bryozoa  can  not  be  considered  as  out 
of   accord   with   such   a   conclusion." 


ALEXANDRIAN  SERIES  119 

appears  to  have  been  derived  from  Shumard's  species  by  the  weaker 
development  of  the  middle  one  of  the  group  of  three  weak  costae  and 
the  suppression  of  the  smaller  striae,  leaving  relatively  broader  flat  spaces 
between  those  that  remain.  The  shells  are  semi-elliptical  in  outline,  a 
little  wider  than  long,  the  hinge  line  straight  and  equaling  the  greatest 
width  of  the  shell,  forming  almost  right  angles  with  the  lateral  margins. 
Ventral  valve  very  slightly  convex,  most  prominent  along  the  median 
portion,  the  convexity  greatest  in  the  umbonal  region,  the  surface  sloping 
to  the  cardinal  extremities  with  a  concave  curvature  and  with  a  gently 
convex  curvature  to  the  lateral  and  anterior  margins.  Beak  pointed  and 
extending  very  slightly  beyond  the  cardinal  margin.  Dorsal  valve  slightly 
concave  or  almost  plane.  Surface  of  both  valves  marked  by  low  radiating 
striae,  about  one-fourth  of  which  extend  to  the  beak.  The  median  one 
on  the  ventral  valve  slightly  stronger  than  the  others.  The  striae  are 
low.  about  one-half  as  numerous  as  in  R.  (Brachy prion?)  mesicosta, 
about  two  occurring  in  the  space  of  1  mm.,  with  rather  broad,  flat  spaces 
between  them.  Besides  the  radiating  striae  there  are  traces  of  numerous 
fine  concentric  lines  which  give  to  the  surface  between  the  striae  a  some- 
what fluctuose  appearance. 

The  dimensions  are :     length,  8  to  9  mm. ;  width,  about  1 1  mm. 

This  species  occurs  in  the  oolite  member  of  the  Edgewood  limestone 
at  Louisiana,  Missouri,  and  south  of  Hamburg,  Illinois. 

Brachyprion  strophcodontoidcs  n.sp. 
(Plate  VI,  figure  4) 
This  species  is  closely  related  to  Rafincsqiiina  (Brachyprion?)  mesi- 
costo var.  mcsistria,  from  which  it  is  chiefly  distinguished  by  the  absence 
of  a  prominent  median  costa  on  the  ventral  valve.  The  shells  are  con- 
cavo-convex, semi-elliptical  in  outline,  length  of  different  specimens  15  to 
20  mm.,  width  about  equaling  or  slightly  exceeding  the  length,  greatest 
at  or  near  the  hinge  line ;  the  lateral  margins  almost  straight,  rounding 
gradually  to  the  regularly  convex  anterior  margin.  Ventral  valve  rather 
strongly  convex  in  the  median  portion,  most  prominent  in  the  umbonal 
region,  the  surface  sloping  rather  steeply,  with  a  concave  curvature  to 
the  cardinal  extremities,  and  with  a  gently  convex  curve  to  the  lateral 
and  anterior  margins.  Cardinal  area  narrow,  beak  low,  scarcely  project- 
ing over  the  cardinal  margin.  Dorsal  valve  gently  and  rather  uniformly 
concave,  the  concavity  distinctly  less  than  the  convexity  of  the  ventral 
valve,  beak  low,  not  projecting.  Surface  of  both  valves  marked  by  very 
numerous  fine  radiating  striae,  some  of  which  are  somewhat  alternating 
in  size,  of  which  four  or  five  occupy  the  space  of  1  mm.,  only  a  few 
extending  to  the  beak.  Occasionally  indistinct  lines  of  growth  are  some- 
times present,  and  in  some  shells  the  ventral  surface  is  gently  undulating. 


120  BIENNIAL  REPORT 

This  species  is  common  in  the  oolite  member  of  the  Edgewood  lime- 
stone at  Louisiana,  and  near  the  mouth  of  Buffalo  Creek,  in  Pike  County, 
Missouri,  and  south  of  Hamburg,  in  Calhoun  County,  Illinois. 

Leptaena  rhomboidalis  (Wilckens) 
(Plate  VI,  figure  3;  and  Plate  III,  figure  11) 
For  synonymy,  and  description  of  this  species  see  a  previous  page  of 
this  paper,  under  the  fossils  of  the  Girardeau  limestone. 

This  form  is  rather  rare  in  the  thick  layers  of  gray  limestone  in  the 
upper  part  of  the  Edgewood  formation,  in  Illinois  and  in  corresponding 
strata  near  Edgewood  and  at  Louisiana,  Missouri. 

Schuchcrtella  propinqua  (Meek  and  Worthen) 

(Plate  VI,  figure  1) 

1868.     Hemipronites   sub  planus?     Meek   and    Worthen,    111.    Geol.    Survey,   vol.    3, 

p.  349. 
1868.     Hemipronites  propinquus.      Meek    and    Worthen,    111.    Geol.    Survey,    vol.    3, 
p.  351. 

Meek  and  Worthen's  description :  "Shell  semi-oval,  or  more  than  semi- 
circular in  outline,  compressed,  resupinate,  subequivalve,  approaching  plano- 
convex ;  hinge  line  about  equaling  the  greatest  breadth  of  the  valves  at  any  point 
farther  forward ;  front  and  anterior  lateral  margins  forming  a  regular  semi- 
circular curve.  Ventral  valve  nearly  flat,  or  a  little  convex  at  the  umbo,  and 
slightly  concave  towards  the  front ;  beak  not  projecting  beyond,  nor  very  distinct 
from,  the  cardinal  margin;  cardinal  area  (mainly  hidden  in  the  matrix  in  our 
specimens)  apparently  of  moderate  breadth,  inclined  backwards,  and  extending  to 
the  extremities  of  the  hinge.  Dorsal  valve  slightly  and  rather  evenly  convex ; 
beak  not  distinct  from  the  cardinal  margin.  Surface  of  both  valves  ornamented 
with  distinct,  abruptly  raised,  radiating  striae,  with  flat  intervening  depressions,  in 
which  there  are  generally  from  one  to  three  or  four  smaller  and  shorter  striae,  one 
of  which  is  sometimes  nearly  as  large  at  the  border  as  the  principal  ones  but  soon 
becomes  smaller,  and  generally  dies  out  near  the  middle  of  the  valves,  while  the 
smallest  ones  are  still  shorter;  crossing  all  of  these,  there  are  numerous  extremely 
fine,  regular,  closely  arranged  concentric  striae. 

"Breadth  of  one  of  the  largest  specimens,  1.30  inches ;  length,  1.05  inches ; 
convexity,  0.18  inch. 

"Locality  and  Position :  Dark  gray  limestone  at  Thebes,  Alexander  County, 
Illinois ;  apparently  of  the  age  of  the  Niagara  division  of  the  Upper  Silurian." 

The  authors  note  that  this  species  differs  from  5".  sub  plana  (Conrad) 
in  being  less  extended  along  the  hinge  line  in  proportion  to  the  length  of 
the  valves ;  in  the  greater  difference  in  the  size  of  the  primary  and  the 
smaller  striae ;  in  the  wider  and  more  flattened  spaces  between  the  radiat- 
ing striae ;  and  in  the  slightly  finer  and  more  crowded  concentric  striae. 
This  species  is  very  abundant  in  the  dark,  shaly  limestone  zone  near  the 
middle  of  the  Edgewood  formation,  in  Illinois,  and  in  a  corresponding 
horizon  in  Pike  County,  Missouri. 


ALEXANDRIAN  SERIES  121 

Schuchertella  cf.  missouriensis   (Shumard) 
(Plate  III,  figures  12  and  13) 
Shells  closely  resembling  this  species  occur  rarely  in  the  Edgewood 
limestone  near  Edgewood,  and  in  the  Noix  oolite  member  at  Louisiana, 
Missouri. 

Schuchertella  missouriensis  var.  convexa  n.var. 
(Plate  VI,  figure  2) 

Shells  resemble  those  of  Schuchertella  propinqua  in  the  character 
of  their  surface  markings,  but  differing  from  the  latter  in  the  much 
smaller  size  and  much  greater  convexity  of  the  ventral  valve.  They  are 
much  like  those  of  5.  missouriensis  (Shumard)  in  size  and  general  pro- 
portions, but  are  distinguished  from  that  species  by  having  every  alternate 
one  of  the  radiating  striae  smaller  and  shorter  than  the  others,  and  not 
extending  one-half  the  distance  from  the  margins  to  the  beak. 

In  the  shells  of  5\  missouriensis  (Shumard)  and  those  of  the  nearly 
related  species  5\  curvistriata,  there  is  a  group  of  3  (sometimes  5)  very 
slender  striae  between  any  two  adjacent  stronger  and  larger  ones. 
Schuchertella  propinqua  and  S.  missouriensis  var.  convexa  appear  to 
have  been  derived  from  the  Girardeau  species  5.  missouriensis  by  the 
stronger  development  of  the  middle  one  of  the  group  of  3  slender  striae 
and  the  suppression  of  the  smaller  one  on  either  side  of  it.  In  some  of 
the  shells  of  5".  missouriensis,  this  tendency  towards  the  greater  develop- 
ment of  the  middle  one  of  the  group  of  three  fine  radiating  striae  than 
of  the  adjacent  one  on  each  side  can  be  seen,  and  occasionally  in  the 
shells  of  the  variety  convexa,  and  5.  propinqua,  traces  of  a  fine  stria  on 
each  side  of  the  smaller  ones  can  be  distinguished.  In  adult  shells  of 
S.  missouriensis  var.  convexa  the  ventral  valve  is  quite  strongly  convex 
(convexity  usually  greater  than  is  indicated  in  the  figure),  most  promi- 
nent in  the  umbonal  region,  from  which  the  surface  slopes  rather  abruptly 
to  the  cardinal  margin,  and  with  a  gentle  curvature  in  the  lateral  and 
anterior  portions.     Dorsal  valve  nearly  flat. 

The  dimensions  are:  length,  about  8  mm.;  width,  about  13  mm.; 
thickness  of  ventral  valve,  2.5  to  3  mm. 

This  variety  is  common  in  the  Noix  oolite  member  of  the  Edge- 
wood  limestone  at  Louisiana  and  near  the  mouth  of  Buffalo  Creek,  in 
Pike  County,  Missouri,  and  south  of  Hamburg  in  Calhoun  County, 
Illinois. 


122  BIENNIAL   REPORT 

Or  this  flabellites  var.  fissiplicata   Foerste. 
(Plate  VI,  figure  7) 
1895.     Orthis  (Dinorthis)  calligramma  var.  fissiplicata,  Foerste,  Ohio  Geol.  Survey, 
vol.  7,  pp.  572  and  573,  pi.  37a,  figures  20a  and  b. 

Shells  differ  from  those  of  Orthis  flabellites  in  the  more  strongly  con- 
vex dorsal  valve,  and  the  much  more  numerous  radiating  striae.  From 
Foerste's  species  Hebertella  daytonensis  and  H.  faitsta,  these  shells  differ 
in  the  flatter,  less  sharp  and  more  rounded  character  of  the  radiating 
striae,  and  the  absence  of  concentric  markings. 

The  ventral  valve  is  moderately  convex  in  the  umbonal  region  from 
which  the  surface  slopes  rather  steeply  to  the  cardinal  and  cardino-lateral 
margins,  and  much  more  gently  to  the  sides  and  front.  Beak  promi- 
nent, somewhat  elevated,  but  not  much  incurved.  Cardinal  area  of  mod- 
erate width.  Dorsal  valve  about  as  convex  as  the  ventral,  with  a  shallow 
undefined  sinus  extending  from  near  the  beak  to  the  anterior  margin. 
The  slope  of  the  surface  rather  uniformly  curving  from  a  short  distance 
in  front  of  the  umbonal  region  in  all  directions.  Beak  small  and  incurved, 
cardinal  area  narrow.  Surface  of  both  valves  marked  with  rather  flat 
radiating  striae  which  divide  once  or  twice  between  the  beaks  and  the 
margins  where  from  55  to  70  may  be  counted  on  large  shells.  No  con- 
centric markings  are  visible. 

The  dimensions  are:  length,  about  18  mm.;  width,  about  equaling 
the  length ;  thickness,  5  to  6  mm. 

Shells  of  this  variety  occur  in  the  oolite  member  of  the  Edgewood 
limestone  at  Louisiana,  and  near  the  mouth  of  Buffalo  Creek  in  Pike 
County,  Missouri,  and  south  of  Hamburg,  in  Calhoun  County,  Illinois. 

Platystrophia  daytonensis  Foerste 
(Plate  VI,  figure  8) 
1885.     Orthis  biforata  var.  lynx  forma  daytoncsis.     Foerste,  Bull.  Sci.  Lab.  Denison 
Univ.,  vol.  1,  p.  82,  pi.  13,  figure  8. 

Foerste's  description  :  "Shell  of  small  size,  wider  than  long,  with  a  subquad- 
rate  outline,  hinge  line  usually  shorter  than  or  equaling  the  breadth  of  the  valves, 
in  one  specimen  exceeding  it  in  size.  The  shells  have  their  outline  distinctly  pre- 
served and  are  found  only  as  simple  valves  showing  their  exterior  surface. 

"Ventral  and  dorsal  valves  with  the  sinus  and  fold  rounded,  the  plications  also 
more  rounded  than  those  of  the  Lower  Silurian  formations,  simple. 

"These  specimens  could  perhaps  be  considered  as  the  young  of  the  forma 
"revcrsata"  were  it  not  for  the  simple  plications  on  both  fold  and  sinus,  which 
remain  simple  while  on  the  corresponding  places  of  the  other  form  there  would  be 
several  additional  plications  intercalated.  Length  of  medium  sized  specimen,  12 
mm. ;  breadth,  18  mm. ;  convexity,  as  well  as  can  be  determined  by  a  comparison 
of  different  single  valves,  9  mm.;  breadth  of  largest  specimen,  24  mm.  Locality 
and  position,  Soldiers  Home,  Clinton  Group." 


ALEXANDRIAN  SERIES  123 

This  species  closely  resembles  the  form  figured  by  Hall  under  the 
name  Delthyris  brachynota29,  but  not  described. 

It  occurs  near  the  top  of  the  fossiliferous  part  of  the  Edgewood 
limestone,  near  Edgewood,  and  south  of  Clarksville,  in  Pike  County, 
Missouri. 

Dalmanella  edgewoodensis  n.sp. 
(Plate  VI,  figures  11,  12,  and  13) 

Shells  of  this  species  are  readily  distinguished  from  those  of  D. 
elegantula  (Dalman)  in  having  the  dorsal  valve  distinctly  more  convex 
than  in  the  typical  shells  of  the  latter  species ;  the  ventral  valve  is 
less  highly  arched  in  the  umbonal  region ;  the  radiating  striae  are  uni- 
formly coarser  and  fewer  in  number ;  and  the  cardinal  area  of  the 
dorsal  valve  is  wider  in  proportion  to  the  width  of  that  of  the  ventral 
valve  by  more  than  one-half.  Our  shells  are  subelliptical  in  outline,  the 
ventral  valve  quite  strongly  convex,  most  prominent  in  the  median  portion 
which  is  not  elevated  in  a  distinct  fold,  beak  pointed,  elevated  but  not 
greatly  incurved ;  delthyrium  nearly  twice  as  high  as  wide,  cardinal  area 
arched  quite  strongly  upward,  about  twice  as  wide  as  that  of  the  dorsal 
valve  which  extends  nearly  in  the  plane  of  the  valves.  Dorsal  valve 
slightly  convex,  with  a  slight  median  depression  extending  from  the  beak 
to  the  front,  beak  not  projecting.  Surface  of  both  valves  marked  by 
prominent  radiating  striae  which  divide  2  to  4  times  between  the  beak 
and  the  margins  where  two  to  three  occur  in  the  distance  of  1  mm., 
curving  upward  over  the  lateral  slopes. 

Shells  of  this  species  are  common  in  the  Edgewood  strata,  in  Mis- 
souri, and  occur  more  sparingly  in  the  upper  part  of  the  Edgewood  forma- 
tion near  Thebes,  Illinois. 

Rhipidomella  tenuilineata  n.sp 
(Plate  VI,  figures  9  and  10) 
Shell  small,  subcircular  to  transversely  subelliptical  in  outline,  as 
wide  or  a  little  wider  than  long,  the  greatest  width  near  the  middle,  length 
about  7  mm.,  width  7  to  8  mm.,  thickness  2.5  mm.,  hinge  line  short,  about 
one-half  the  greatest  width  of  the  shell.  Ventral  valve  rather  strongly 
convex,  most  prominent  in  the  umbonal  region,  the  surface  sloping  rather 
abruptly  to  the  cardinal  margin  and  with  a  moderately  convex  curvature 
to  the  front  and  lateral  margins,  the  median  portion  most  prominent  but 
scarcely  elevated  into  a  well-defined  fold.  Dorsal  valve  much  less  convex 
than  the  ventral,  the  curvature  nearly  uniform,  the  slope  to  the  cardinal 
margin  a  little  steeper  than  over  the  lateral  and  front  portions,  the  middle 


'Geology  of   New   York,  Report  of  fourth  district,  p.   70,   fig.   6,   1843. 


Oi 


124  BIENNIAL   REPORT 

part  of  the  valve  flattened  or  depressed  in  a  broad,  shallow  sinus  which 
extends  nearly  to  the  beak.  Surface  of  both  valves  marked  by  numerous 
very  fine  radiating  striae  which  divide  three  or  four  times  in  passing 
from  the  beaks  to  the  margins ;  a  number  of  concentric  lines  of  growth 
are  also  visible  under  a  lens. 

These  shells  differ  from  those  of  other  known  species  of  the  genus, 
except  R.  saffordi  Foerste,  in  their  small  size,  the  very  numerous,  exceed- 
ingly fine,  radiating  striae,  and  the  broad,  flattened  or  depressed  median 
portion  of  the  dorsal  valve.  From  Foerste's  species  they  may  be  dis- 
tinguished by  the  greater  width  near  the  hinge  line,  which  gives  to  the 
shells  a  more  circular  or  elliptical  outline,  and  the  much  finer  and  more 
numerous  radiating  striae.  They  occur  in  the  oolite  member  of  the 
Edgewood  limestone  at  Louisiana,  and  near  the  mouth  of  Buffalo  Creek 
in  Pike  County,  Missouri. 

Pentamerus  parvulus  n.sp. 
(Plate  VII,  figures  18,  19,  20,  and  21) 

Shell  biconvex,  subovate  in  outline,  sides  rather  straight  and  front 
rounded,  width  equaling  or  a  little  less  than  the  length,  widest  anterior  to 
the  middle,  apical  angle  60  to  75  degrees,  valves  subequally  convex. 
Ventral  valve  moderately  convex,  most  arcuate  in  the  umbonal  region, 
beak  prominent,  acuminate,  not  much  incurved,  cardinal  and  lateral  slopes 
steep,  anterior  portion  of  shell  moderately  convex,  median  portion  of 
the  valve  depressed  in  a  rather  shallow  sinus  which  extends  more  than 
three-fourths  of  the  distance  from  the  front  to  the  beak,  broad  in  the 
anterior  portion  where,  in  occasional  shells,  there  is  a  slight  tendency 
towards  the  development  of  a  low  indistinct  ridge  in  the  bottom.  Beneath 
the  beak  is  a  prominent  spondylium,  longitudinally  three  lobed,  and  sup- 
ported in  the  posterior  portion  by  a  very  short  median  septum.  Dorsal 
valve  slightly  more  convex  than  the  ventral,  most  prominent  along  the 
median  line  which  is  somewhat  elevated  from  near  the  beak  to  the  front 
in  a  poorly  defined  mesial  fold,  (the  illustration  of  this  valve  makes  it 
appear  a  little  too  broad  in  proportion  to  its  length)  cardinal  and  lateral 
slopes  rather  steep,  surface  more  gently  convex  in  the  anterior  portion, 
beak  pointed  but  not  much  incurved,  spondylium  narrower  on  the  bottom 
than  that  of  the  ventral  valve,  not  longitudinally  lobed,  and  supported 
for  the  greater  portion  of  its  length  by  a  rather  strong  median  septum. 
Surface  of  each  valve  marked  by  a  number  of  concentric  lines  of  unequal 
strength. 

This  species  differs  from  Clorindaf  thebesensis  in  its  smaller  size, 
narrower  outline,  more  acuminate  beaks,  and  absence  of  radiating  striae. 
Associated  with  it  are  a  few  shells  of  somewhat  similar  proportions,  but 


ALEXANDRIAN  SERIES  125 

showing  three  to  five  faint  rounded  radiating  plications  on  the  anterior 
half  of  the  shell,  which  are  thought  to  represent  Clorinda?  thebesensis. 
This  species  occurs  in  the  Noix  oolite  member  of  the  Edgewood  limestone 
in  the  vicinity  of  Louisiana  and  Clarksville,  Missouri,  and  below  Ham- 
burg in  Calhoun  County,  Illinois. 

Clorinda f  thebesensis  n.sp. 
(Plate  VII,  figures  7  and  8) 

Shells  of  medium  or  small  size,  biconvex,  more  or  less  subquadrate 
to  subovate  in  outline,  about  as  wide  as  long,  the  greatest  width  near  the 
middle  of  the  shell.  Ventral  valve  rather  strongly  convex,  most  prom- 
inent in  the  umbonal  region ;  median  area  becoming  depressed  in  a  broad 
shallow  sinus  which  widens  towards  the  front,  and  bears  a  broad,  very 
slightly  raised  elevation.  The  front  margin  somewhat  extended,  fitting 
into  a  corresponding  median  notch  at  the  front  of  the  dorsal  valve ; 
beak  pointed,  much  elevated  and  incurved,  the  sides  sloping  away  at  an 
angle  of  about  100  degrees.  Dorsal  valve  convex,  with  an  indistinct 
median  fold  appearing  anterior  to  the  umbo  and  widening  to  the  front, 
which  is  notched  for  the  reception  of  the  extension  of  the  ventral  valve. 
On  some  shells  traces  of  three  to  five  low  rounded  plications  appear  on 
the  anterior  half  of  the  shell,  but  generally  these  are  absent ;  beak  pointed 
and  strongly  incurved  beneath  that  of  the  ventral  valve.  Surface  of  both 
valves  showing  fine  concentric  lines  which  are  more  numerous  near  the 
surface. 

The  dimensions  are:  length,  12  to  15  mm.;  width,  about  equaling 
the  length ;  thickness,  8  to  10  mm. 

In  some  respects  this  species  resembles  C.  ventricosa  (Hall),  of  the 
Niagara,  from  which  it  differs  in  its  much  less  ventricose  form,  in  the 
relatively  smaller  convexity  of  the  ventral  valve,  and  in  its  shorter 
median  prolongation  at  the  front.  It  is  also  disinguished  from  C.  forni- 
eata  (Hall)  by  its  less  ventricose  and  more  subquadrate  form,  by  the 
less  prominent  umbo  of  the  ventral  valve,  and  the  relatively  greater  con- 
vexity of  the  dorsal  valve.  The  species  is  common  in  the  thick  limestone 
layer  in  the  upper  part  of  the  Edgewood  formation  near  Thebes,  Illinois, 
where  it  is  associated  with  Whit  field  ell  a  billingsana  and  Lophospira 
thebesensis.  Shells  thought  to  represent  the  same  species  occur  also  in 
the  Noix  oolite  member  at  Louisiana  and  near  Clarksville,  in  Pike 
County,  Missouri. 

Rhynchotreta  parva  n.sp. 
(Plate  VII,  figures  9  and  10) 

Shell  subtriangular  or  cuneiform  in  outline,  the  valves  moderately 
and  about  equally  convex.     The  width  about  two-thirds  of  the  length, 


126  BIENNIAL  REPORT 

greatest  in  the  anterior  portion ;  the  largest  specimens  measure  13  mm. 
long,  about  9.5  mm.  wide,  and  4.5  mm.  thick.  Much  smaller  specimens, 
3.5  to  4  mm.  in  length,  are  common  in  the  oolite.  The  apical  angle  is 
about  46  degrees.  The  sides  are  nearly  straight  from  the  beak  for  about 
two-thirds  of  the  length,  whence  they  round  off  to  the  front  margin  which 
is  gently  convex.  The  lateral  slopes  are  steep,  forming  nearly  right 
angles  with  the  plane  of  the  valves.  The  ventral  valve  has  a  prominent, 
erect  beak,  the  greatest  convexity  in  the  umbonal  region,  the  surface 
sloping  abruptly  to  the  lateral  margins  and  very  gently  in  the  anterior 
portion.  No  distinct  fold  or  sinus  is  present.  The  dorsal  valve  is  most 
convex  in  the  posterior  region,  the  median  portion  slightly  depressed 
towards  the  beak  which  is  small  and  incurved.  The  posterior  slopes 
gently  convex.  The  surface  of  each  valve  is  marked  by  14  to  16  simple 
plications  which  extend  to  the  beak  and  are  about  equal  in  width  to  the 
intervening  furrows.     No  distinct  concentric  markings  are  visible. 

This  species  most  nearly  resembles  Rhynchotreta  simplex  Foerste, 
from  which  it  is  distinguished  by  its  smaller  size  and  narrower  outline, 
by  the  greater  length  in  proportion  to  the  width,  the  more  nearly  trun- 
cate anterior  margin  and  the  greater  number  of  plications.  Shells  of 
this  species  are  common  in  the  oolite  member  of  the  Edgewood  limestone 
at  Louisiana,  Missouri,  and  south  of  Hamburg,  Illinois. 

Rhynchotreta  thebesensis  Foerste 
(Plate  VI,  figures  19  and  20) 
1909.     Rhynchotreta    thebesensis.     Foerste,    Bull.    Sci.    Lab.    Denison   Univ.,    April, 
1909,  p.  94,  figures  66a-66c. 

Foerste's  description:  "Shell  cuneiform,  with  long  flat  sides  diverging  at  an 
angle  of  60  to  70  degrees,  with  an  acuminate  beak.  The  anterior  outline  is  rounded, 
and  the  depth  of  the  shell  is  considerable  for  one  of  this  type.  In  a  shell  having 
a  width  of  14.5  mm.,  the  depth  was  10.5  mm.,  the  length  of  the  brachial  valve  was 
14.5  mm.,  and  the  length  of  the  pedicle  valve  was  estimated  at  slightly  over  15.5 
mm.  Near  the  beak  of  the  brachial  valve  a  few  specimens  show  a  slight  median 
concavity.  The  two  medium  plications  are  slightly  raised  anteriorly  above  the 
general  convexity  of  this  part  of  the  shell.  On  each  side  of  these  median  plica- 
tions there  are  four  distinct  and  one  indistinct  plication,  reduced  sometimes  to  3 
distinct  and  1  indistinct  one.  On  the  pedicle  valve  there  is  a  median  plication  with 
4  distinct  and  1  indistinct  plication  on  each  side.  This  median  plication,  in  some 
specimens,  terminates  in  a  slight  depression  anteriorly,  in  others  the  plication  on 
each  side  of  the  median  plication  also  is  involved  so  that  there  is  a  broad  flattening 
or  slight  depression,  without  the  appearance  of  a  sinus.  There  is  no  evidence  of 
a  deltidium  partly  closing  the  delthyrium. 

"Strata  of  uncertain  age,  but  evidently  lower  Niagaran.     Thebes,  Illinois." 

This  species  is  clearly  related  to  the  Clinton  form,  R.  robnsta  Hall, 
but  differs  from  it  in  the  much  less  pronounced  fold  and  sinus,  which  are 
usually  only  slightly  developed  or  wanting,  in  the  Edgewood  species. 


ALEXANDRIAN  SERIES  127 

Rhynchotreta  thcbcsensis  var.  multistriata  n.var. 
(Plate  VI,  figures  21  and  22) 

Associated  with  the  shells  of  Rhynchotreta  thebcsensis  in  the  Edge- 
wood  limestone  near  Thebes,  Illinois,  are  a  number  which  differ  from 
those  of  the  typical  species,  figured  and  described  by  Foerste  in  the  less 
sharply  acuminate  ventral  beak  and  more  symmetrical  outline,  and  in  the 
finer  and  more  numerous  regular  radiating  plications,  two  of  which  are 
slightly  elevated  at  the  front  in  the  mesial  portion  of  the  dorsal  valve, 
and  one  or  two  of  the  central  plications  of  the  ventral  valve  are  slightly 
depressed  near  the  anterior  margin.  Entire  surface  marked  by  14  to  17 
simple  radiating  plications,  about  two  of  which  on  the  extreme  lateral 
margins  are  smaller  than  those  on  the  other  portions  of  the  shell. 

The  dimensions  are:  length,  18  to  20  mm.;  greatest  width,  17  to 
18  mm. ;  thickness,  8  to  10  mm. 

This  variety  is  not  rare  in  the  Edge  wood  limestone  near  Thebes, 

Illinois. 

Camar  otocchia?  concinna  n.sp 

(Plate  VII,  figures  4  and  5) 

This  species  differs  from  Camar otoechia  indianensis  (Hall),  which 
it  resembles  in  some  respects,  in  having  fewer  plications  in  the  sinus  and 
on  the  fold  of  the  ventral  and  dorsal  valve  respectively,  and  usually  a 
smaller  number  on  the  lateral  slopes.  Shell  small,  subtriangular  to 
broadly  ovate  in  outline,  length  and  width  about  equal,  valves  subequally 
convex ;  front  margin  truncate  or  very  gently  rounded.  Ventral  valve 
convex  in  the  umbonal  region,  the  median  portion  depressed  into  a  sinus 
which  begins  on  the  umbo  and  deepens  toward  the  front,  where  it  is  not 
much  produced ;  beak  small,  acuminate,  incurved.  Dorsal  valve  most 
convex  in  the  median  portion,  with  a  prominent  fold  extending  about 
two-thirds  of  the  length  of  the  valve,  and  increasing  in  height  from  the 
umbo  to  the  front ;  beak  small,  incurved  beneath  that  of  the  ventral  valve. 
Surface  of  each  valve  marked  by  simple,  sub-angular,  radiating  plications, 
two  of  which  occupy  the  sinus,  three  are  elevated  on  the  fold,  and  four, 
with  sometimes  a  trace  of  a  fifth,  occur  on  each  of  the  lateral  slopes. 
Around  the  front  and  lateral  margins  there  are  a  few  prominent,  sub- 
imbricating  concentric  striae.  The  grooves  between  the  plications  are 
produced  at  the  front  and  sides  into  acutely  angular  serrations  which  fit 
into  corresponding  angular  notches  beneath  the  plications  of  the  opposite 
valve. 

The  dimensions  are :  length,  about  6  mm. ;  width,  about  equal  to 
the  length ;  thickness,  4  to  5  mm. 

Shells  of  this  species  were  found  in  the  Edgewood  strata  in  Pike 
County,  Missouri,  and  near  Thebes,  Illinois. 


128  BIENNIAL   REPORT 

Camarotoechia?  antiqua  n.sp. 
(Plate  VII,  figures  1  and  2) 
Shells  in  some  respects  resembling  those  of  Rhynchonella?  janea 
Billings,  with  which  they  are  associated,  but  are  distinguished  from  that 
species  in  having  a  more  sharply  defined  fold  and  sinus,  each  of  which 
bears  one  more  plication  than  in  R.f  janea.  Our  species  also  has  fewer 
plications  on  the  lateral  slopes  of  each  valve,  and  the  front  margin  appears 
more  distinctly  truncate. 

Shell  subovate  to  pentangular  in  outline ;  apical  angle  about  90 
degrees ;  valves  about  equally  convex,  length  and  width  subequal,  the 
greatest  width  near  the  middle.  Ventral  valve  with  the  greatest  convexity 
in  the  umbonal  region,  the  median  portion  depressed  into  a  sinus  which 
begins  about  one-fourth  the  distance  from  the  beak  to  the  front,  and 
becomes  prominent  towards  the  anterior  margin,  where  it  is  occupied 
by  four  angular  plications ;  beak  acute,  elevated  and  incurved  over  the 
hinge  line.  Dorsal  valve  with  mesial  fold  distinct  for  about  two-thirds 
of  its  length  and  bearing  5  angular  plications,  the  exterior  one  on  either 
side  being  slightly  smaller  than  the  others  ;  beak  incurved  beneath  that  of 
the  opposite  valve.  Surface  marked  by  4  angular  plications  on  each  side 
of  the  fold  and  sinus,  and  sometimes  with  trace  of  a  fifth ;  a  few  fine 
concentric  lines  and  an  occasional  more  prominent  line  of  growth  are 
also  present.  The  dimensions  are :  length  about  12  mm. ;  width  about 
equal  to  the  length ;  thickness  about  7  mm. 

Shells  of  this  species  occur  in  the  upper  part  of  the  Edgewood  forma- 
tion in  Alexander  County,  Illinois,  and  near  Edgewood,  Missouri. 

Rhynchonella?  janea  Billings 

(Plate  VII,  figure  3) 

1866.     Rhynchonella  janea.     Billings,  Catalogue  Silurian  Fossils  of  Anticosti,  p.  43. 

1890.     Rhynchonella  janea.     Foerste,  Proc.  Boston  Soc.  Nat.  Hist.,  vol.  24,  p.  316, 

pi.  5,  figures  23  and  24. 
1895.     Rhynchonella  janea.     Foerste,  Ohio  Geol.   Survey,  vol.  7,  pi.  30,  figures  23 

and  24. 
Billings'  description:  "Subovate,  apical  angle  about  80  degrees;  sides  some- 
what straight  in  the  upper  half,  rounded  in  the  lower  half;  about  one-half  of  the 
front  margin  truncated  or  nearly  straight.  Ventral  valve  moderately  convex ;  sinus 
deep  and  concave  at  the  front,  one-third  the  whole  width,  dying  out  near  the  umbo ; 
sides  of  the  sinus  with  one  or  two  prominent  ribs  from  which  there  is  a  somewhat 
flat  slope  to  the  margin  ;  umbo  prominent  but  narrow  ;  beak  elevated  about  half  a 
line  above  the  hinge  and  moderately  incurved ;  there  appears  to  be  a  circular  for- 
amen beneath  it.  Dorsal  valve  more  uniformly  convex  than  the  ventral;  mesial 
fold  dying  out  at  about  two-thirds  the  length.     There  are  four  angular  ribs  on  the 


ALEXANDRIAN  SERIES  129 

fold  and  three  on  the  sinus ;   from  six  to  eight  on  each  side  or  from  sixteen  to 
twenty  in  all  on  each  valve.     Length  6  or  7  lines ;  greatest  width  about  the  same. 
"This  species  differs  from  R.  anticosticnsis  in  having  the  beak  more  incurved." 

Shells  that  cannot  be  distinguished  with  certainty  from  the  above 
species  were  found  in  the  Edgewood  formation  in  Alexander  County, 
Illinois,  and  near  Edgewood  in  Pike  County,  Missouri. 

Protozeuga  sulcocarinata  n.sp. 

(Plate  VII,  figure  6) 

For  description  of  this   species   refer  to  the   description  of   fossils 

from  the  Girardeau  limestone.     Shells  that  are  thought  to  be  identical 

with  this  common  species  of  the  Girardeau  limestone  are  not  rare  in  the 

Noix  oolite  member  of  the  Edgewood  formation  at  Louisiana,  Missouri. 

A  try  pa  praemarginalis  n.sp. 
(Plate  VI,  figures  14,  15,  and  16) 
Shells  resemble  A  try  pa  marginalis  (Dalman)  in  some  of  their  char- 
acters, but  differ  from  that  species  in  the  less  flattened  and  expanded 
shape,  the  shorter  hinge  line,  and  more  circular  outline,  in  the  more 
strongly  convex  ventral  valve  which  is  not  so  reflexed  at  the  lateral  and 
front  margins,  and  in  the  absence  of  such  numerous  equi-distant  fine 
concentric  lines.  The  shells  are  subcircular  in  outline,  length  and  width 
about  equal,  hinge  line  rather  short  and  valves  subequally  convex.  Ven- 
tral valve  strongly  convex  along  the  median  portion,  the  greatest  depth 
a  little  posterior  to  the  middle.  The  surface  sloping  rather  abruptly 
to  the  cardinal  margin,  almost  straight  from  the  convex  median  portion 
to  the  lateral  margins,  and  gently  convex  in  the  anterior  portion,  the 
mesial  part  of  the  valve  occupied  by  a  rather  deep  sinus  extending  to  the 
beak,  narrower  in  the  posterior  half  of  the  shell  than  in  the  anterior 
portion,  and  slightly  produced  in  front,  bordered  on  each  side  by  a  prom- 
inent ridge.  Beak  prominent,  pointed,  and  somewhat  incurved  over  the 
hinge  line.  Dorsal  valve  about  the  same  convexity  as  the  ventral,  the 
deepest  in  the  umbonal  region,  from  which  the  surface  curves  rather 
steeply  to  the  cardinal  margin,  and  is  gently  convex  in  the  lateral  and 
anterior  portions,  with  a  prominent  mesial  fold  which  is  narrow  for 
about  one-half  the  distance  from  the  beak,  becoming  wider  in  the  anterior 
portion,  somewhat  flattened  along  the  middle,  and  separated  from  the 
lateral  portions  of  the  shell  by  a  deep  groove ;  beak  pointed  and  incurved 
closely  beneath  that  of  the  ventral  valve.  Surface  of  both  valves  marked 
by  radiating  costae,  about  three  on  each  side  of  the  fold  and  sinus,  which 
extend  to  the  beak,  and  bifurcate  two  or  three  times  before  reaching  the 
margins  so  that  they  appear  to  be  clustered  in  three  bundles  on  each  side 


130  15IKNNIAL   REPORT 

of  the  fold  and  sinus,  about  six  present  on  the  fold  apparently  arising 
from  a  single  one  at  the  beak ;  two  or  three  costae  occupy  each  side  of 
the  mesial  sinus,  arising  from  the  bifurcations  of  the  strong  ridges  that 
border  the  sinus.  Sometimes  there  is  also  a  central  costa  occupying  the 
bottom  of  the  sinus.  There  are  occasional  lines  of  growth,  especially  near 
the  margins,  but  the  fine  regular  concentric  lines,  so  characteristic  in 
A.  marginalis,  are  not  present. 

The  dimensions  are:  length,  12  to  15  mm.;  width,  12  to  15  mm.; 
thickness,  about  7  mm. 

This  species  is  common  in  the  Edgewood  limestone,  immediately 
below  the  Bowling  Green  member,  in  the  vicinity  of  Edgewood  and 
Watson  Station,  and  at  other  places  in  Pike  County,  Missouri,  and  is 
found  also  near  Thebes,  Illinois. 

Atrypa  putilla   (Hall  and  Clarke) 
(Plate  VI,  figure  25) 
1893.     Zygospira  putilla.     Hall  and  Clarke,   Paleontology  New  York,  vol.  8,  pt.  2, 
p.  365,  pi.  54,  figures  35-37 ;  pi.  83,  figures  29  and  30. 

Hall  and  Clarke's  description :  "Shell  small,  elongate-suboval  in  outline. 
Pedicle  valve  the  more  convex ;  umbo  narrowed,  apex  acute,  delthyrium  unclosed. 
Medially  this  valve  is  elevated  by  a  strong  double  plication,  the  parts  of  which 
diverge  anteriorly,  leaving  a  flat,  low  depression  between  them,  and  in  this  lies  a 
single  faint  plication.  The  lateral  slopes  are  considerably  depressed,  and  each  bears 
from  four  to  seven  coarse,  often  irregular  plications,  only  a  part  of  them  reaching 
the  beak. 

"The  brachial  valve  is  depressed-convex,  with  a  conspicuous  median  fold, 
grooved  longitudinally  and  bounded  by  deep  marginal  depressions.  The  lateral 
slopes  are  more  convex  than  on  the  other  valve,  but  are  similarly  plicated.  Surface 
of  the  valves  usually  without  concentric  growth  lines. 

"An  average  example  has  a  length  of  8  mm.,  and  a  greatest  width  of  7  mm. 

"Hudson  River  group.     Near  Edgewood,  Pike  County,  Missouri." 

The  form  of  this  species  that  is  found  near  Thebes,  Illinois,  is  slightly 
larger  than  the  average  size  of  the  shells  occuring  near  Edgewood,  Mis- 
souri. The  shape  and  surface  markings  of  the  shells  in  the  two  localities 
are  similar,  and  some  of  the  larger  individuals  from  Missouri  are  similar 
in  size  to  the  normal  Illinois  specimens.  Among  a  large  number  of  shells 
of  this  species  are  found  some  in  which  all  of  the  radiating  striae  are 
entirely  simple ;  others  in  which  only  one  or  two  of  the  striae  on  either 
side  show  traces  of  division ;  and  still  others  in  which  nearly  all  of  the 
striae  divide  between  the  beak  and  the  margins,  and  the  shells  approach 
A.  pracmarginalis  in  general  appearance.  This  species  is  also  common 
in  the  Noix  oolite  member  at  Louisiana,  Missouri. 


ALEXANDRIAN  SERIES  131 

Atrypa  tuhulistriata  n.sp. 
(Plate  VII,  figures  23  and  24) 

Shells  suborbicular  in  outline,  the  length  and  width  nearly  equal, 
the  hinge  line  in  old  shells  about  three-fourths  the  greatest  width,  cardinal 
extremities  rounded.  Ventral  valve  moderately  convex,  most  prominent 
in  the  umbonal  region,  beak  pointed  and  somewhat  incurved,  the  cardinal 
slopes  steep,  lateral  and  anterior  slopes  more  gently  convex,  mesial  part 
of  the  valve  depressed  into  a  prominent  sinus  that  extends  nearly  to  the 
beak,  becoming  deeper  and  broader  towards  the  anterior  margin  where 
it  is  produced  into  a  short  lingual  extension,  marked  by  about  four  or 
five  plications  which  appear  to  be  formed  by  the  bifurcation  of  the  lateral 
bounding  plications.  Dorsal  valve  more  convex  than  the  ventral,  rather 
strongly  arched  in  the  umbonal  region,  beak  small  and  closely  incurved, 
the  cardinal  slopes  very  steep,  lateral  and  anterior  slopes  moderately 
convex,  mesial  fold  extending  nearly  to  the  beak,  prominently  elevated 
on  the  anterior  half  of  the  shell,  marked  by  four  to  six  plications  wdiich 
arise  by  the  bifurcation,  once  or  twice,  of  the  two  longest  ones.  The 
lateral  slopes  of  both  valves  are  each  marked  near  the  margin  by  six 
to  twelve  somewhat  irregular  radiating  plications  which  arise  from  the 
bifurcation,  once  or  twice,  of  about  three  original  ones,  the  longest  not 
extending  quite  to  the  beak.  Surface  of  both  valves  with  prominent 
concentric  ridges  or  lamellae,  1  to  1.5  mm.  apart,  which  are  slightly 
inflated  where  they  cross  the  plications. 

The  dimensions  are :  length  of  different  shells,  12  to  17  mm. ;  width, 
about  equal  to  length ;  thickness,  5  to  10  mm. 

In  appearance  this  species  somewhat  resembles  Atrypa  nodostriata 
Hall,  from  which  it  differs  in  the  relatively  deeper  dorsal  valve,  in  the 
fold  and  sinus  extending  more  nearly  to  the  beak,  and  with  more  sharply 
defined  borders,  and  in  the  radiating  striae  not  extending  quite  to  the 
beak.  These  shells  are  common  in  the  Noix  oolite  member  of  the  Edge- 
wood  formation  at  Louisiana,  and  near  the  mouth  of  Buffalo  Creek,  in 
Pike  County,  Missouri,  and  south  of  Hamburg  in  Calhoun  County, 
Illinois. 

Spirifer  (Delthyris)  sp. 
(Plate  VII,  figure  22) 

This  small  species  of  Spirifer,  which  is  represented  by  only  a  single 
ventral  valve,  resembles  Delthyris  sulcata  Hisinger  in  some  respects,  but 
lacks  the  imbricating  concentric  lamellae  of  that  genus.  The  valve  is 
moderately  convex,  length  and  width  subequal,  about  5  millimeters,  with 
a  fairly  well  defined  mesial  sinus,  on  either  side  of  which  are  four  plica- 
tions and  a  trace  of  a  fifth. 


132  BIENNIAL  REPORT 

This  species  is  rare  in  the  upper  part  of  the  Edgewood  formation, 
near  Thebes,  Illinois. 

Homocospira  fiscellostriata  n.sp. 
(Plate  VI,  figures  23  and  24) 

Shell  biconvex,  subovate  in  outline,  somewhat  longer  than  wide. 
Ventral  valve  more  convex  than  the  dorsal,  the  greatest  convexity  in 
the  umbonal  region  from  which  the  surface  slopes  rather  steeply  to  the 
cardinal  and  cardino-lateral  margins,  and  more  gently  to  the  sides  and 
front ;  the  mesial  portion  of  the  valve  somewhat  elevated,  with  a  prom- 
inent stria  on  each  side  of  the  median  line;  in  the  furrow  between  these 
striae  is  a  rounded  ridge  which  extends  nearly  three-fourths  of  the  dis- 
tance from  the  front  to  the  beak.  The  beak  is  prominent  and  pointed, 
but  not  much  incurved  over  the  hinge  line.  Dorsal  valve  moderately 
convex,  the  greatest  depth  a  little  posterior  to  the  middle,  from  which 
the  surface  slopes  with  a  rather  uniform  curvature  to  the  cardinal,  lateral 
and  anterior  margins ;  the  mesial  portion  of  the  valve  bears  a  slight 
depression  which  is  occupied  by  a  low  ridge  extending  nearly  to  the  beak 
and  is  divided  by  a  shallow  furrow  in  the  anterior  half  of  its  length,  with 
a  trace  of  an  additional  division  near  the  front  margin.  The  beak  is 
small  and  closely  incurved  beneath  that  of  the  ventral  valve.  Surface 
of  both  valves  marked  by  radiating  striae  of  which  about  four  on  each 
side  of  the  median  line  of  the  valves  extend  to  the  beaks ;  of  these,  the 
two  adjacent  to  the  median  line  on  each  valve  usually  divide  twice,  while 
some  of  the  others  divide  once  and  others  divide  twice  between  the  beak 
and  the  margin.    No  distinct  concentric  lines  of  growth  are  visible. 

The  dimensions  are :  length,  7  to  8  mm. ;  width,  about  6  mm. ;  thick- 
ness, 2  to  2.5  mm. 

This  species  more  nearly  resembles  Homoeospira  sub  circular  is,  with 
which  it  is  associated  in  the  Edgewood  limestone,  than  any  other  known 
species,  but  differs  from  that  form  in  the  somewhat  smaller  size,  and  the 
more  numerous  and  irregular  divisions  of  the  radiating  striae.  The  latter 
character  will  also  serve  to  distinguish  this  species  from  all  other  known 
species  of  the  genus.  Shells  of  H.  fiscellostriata  occur  in  the  Noix  oolite 
phase  of  the  Edgewood  limestone  at  Louisiana,  Missouri. 

Homoeospira  subcircularis  n.sp. 

(Plate  VI,  figures  26  and  27) 

Shells    moderately    biconvex,    sub-circular    in    outline ;    ventral   valve 

most  prominent  in  the  median  portion,  the  surface  curving  strongly  from 

the  umbonal  region  to  the  cardinal  margin  and  a  little  more  gently  to  the 

sides  and  front;  mesial  sinus  narrow  in  the  posterior  portion,  extending 


ALEXANDRIAN  SERIES  133 

to  the  beak,  bordered  on  each  side  by  a  prominent  angular  ridge,  the 
bottom  occupied  by  a  simple  elevation  in  the  anterior  half  of  the  shell, 
beak  prominent  and  rather  strongly  incurved.  Dorsal  valve  a  little  less 
convex  than  the  ventral,  deepest  near  the  center,  from  which  portion  the 
surface  slopes  with  about  equal  convexity  to  the  cardinal,  lateral  and 
anterior  margins ;  mesial  fold  not  much  elevated  above  the  sides,  extending 
to  the  beak,  much  wider  in  the  anterior  half  of  the  shell,  somewhat 
flattened  on  top,  and  divided  in  the  anterior  portion  by  a  furrow  which 
extends  more  than  one-half  the  distance  from  the  front  to  the  beak,  the 
latter  rather  small  and  closely  incurved  beneath  that  of  the  ventral  valve. 
Surface  of  both  valves  marked  by  seven  or  eight  subangular  costae  on 
each  side  of  the  fold  and  sinus,  of  which  the  two  nearest  the  fold  and 
sinus  on  each  side  divide  once  on  the  posterior  one-third  of  the  shell.  No 
concentric  lines  are  visible. 

The  dimensions  are :  length,  8  to  9  mm. ;  width,  about  equaling  the 
length ;  thickness,  4  to  4.5  mm. 

This  species  is  more  closely  related  to  Homoeospira  fisccllostriata 
than  to  any  other  known  species,  but  differs  from  it  in  the  fewer  striae 
that  divide,  and  the  less  numerous  divisions  of  the  radiating  striae.  It 
also  somewhat  resembles  H.  beecheri  Foerste,  from  which  it  may  be 
distinguished  by  the  bifurcation  of  the  two  striae  nearest  and  on  each 
side  of  the  median  fold  and  sinus. 

Shells  of  this  species  are  common  in  the  Xoix  oolite  member  of 
the  Edgewood  limestone  in  the  vicinity  of  Louisiana,  Missouri. 

Hindella?  ambigua  n.sp. 
(Plate  VI,  figures  17  and  18) 

Shells  somewhat  resembling  Hindella  umbonata  (Billings),  from 
which  they  differ  in  the  relatively  greater  width  in  proportion  to  the 
length,  especially  posterior  to  the  middle,  in  the  lower  ventral  beak,  and 
in  the  less  deep  excavation  bordering  the  hinge  line.  They  differ  from 
Hindella  prinstana  (Billings)  in  the  more  elongate  form  of  the  shell,  the 
relatively  shorter  hinge  line,  and  the  more  prominent  ventral  beak. 

The  shells  of  this  species  show  some  variation  in  shape  and  size,  but 
are  bi-convex,  subovate  in  outline,  the  greatest  width  at  or  slightly 
posterior  to  the  middle.  Ventral  valve  most  convex  in  the  umbonal 
region,  the  surface  curving  steeply  to  the  cardino-lateral  margins,  and 
sloping  more  gently  toward  the  sides  and  front.  In  some  shells  a  faint 
depression  appears  in  the  median  line  for  a  short  distance  from  the 
front  margin,  in  others  no  sinus  is  discernible ;  beak  rather  small,  pointed, 
and  strongly  incurved  over  that  of  the  dorsal  valve,  with  the  umbonal 
surface  of  which  it  is  not  quite  in  contact.    Dorsal  valve  less  convex  than 


134  BIENNIAL  REPORT 

the  ventral,  the  greatest  convexity  in  the  umbonal  portion,  sloping  quite 
steeply  towards  the  cardinal  regions  and  rather  evenly  towards  the  front 
and  lateral  margins;  beak  incurved,  and  concealed  beneath  that  of  the 
ventral  valve.  Surface  of  both  valves  marked  by  rather  fine  concentric 
lines  which  are  most  conspicuous  near  the  margins. 

The  dimensions  are:  length,  15  to  20  mm.;  width,  13  to  18  mm.; 
thickness,  9  to  14  mm. 

Shells  of  this  species  are  not  rare  in  the  Edgewood  strata  near 
Edgewood,  in  Pike  County,  Missouri.  Fragments  of  shells  thought  to 
represent  the  same  species  were  also  found  in  the  upper  part  of  the 
Edgewood  formation  in  Alexander  County,  Illinois. 

Whit  field  ell  a  billing  sana  (Meek  and  Worthen) 
(Plate  VII,  figures  11  and  12) 
1868.  Ccntronclla  billingsana.  Meek  and  Worthen,  111.  Geol.  Survey,  vol.  3,  p.  352, 
figures  a,  b,  c ;  pi.  6,  figures  5a-5c. 
Meek  and  Worthen's  description :  "Shell  attaining  a  moderately  large  size, 
subovate  in  form ;  valves  nearly  equally  convex,  the  ventral  being  a  little  more 
gibbous  than  the  other,  particularly  in  the  umbonal  region ;  greatest  breadth  near 
the  middle,  or  slightly  in  advance  of  it;  posterior  lateral  slopes  nearly  straight,  or 
sometimes  a  little  concave  in  outline,  and  converging  to  the  beaks  at  various  angles 
of  from  70  to  80  degrees ;  front  usually  rather  narrowly  rounded,  faintly  subtrun- 
cate,  or  very  slightly  sinuous.  Dorsal  valve  regularly  convex,  and  without  any 
traces  of  a  sinus  or  mesial  ridge ;  beak  rather  gibbous  and  distinctly  incurved. 
Ventral  valve  with  a  shallow,  rather  narrow  mesial  sinus,  generally  moderately 
well  defined  at  the  front,  and  extending  to  the  central  region,  where  it  gradually 
becomes  obsolete ;  beak  moderately  prominent,  rather  pointed,  somewhat  arched, 
with  apparently  a  very  small  perforation  at  the  extremity,  connected  when  the  del- 
tidium  is  removed,  with  a  comparatively  large  triangular  opening  extending  to 
the  incurved  beak  of  the  opposite  valve.  Surface  of  both  valves  marked  with 
obscure  concentric  striae  of  growth. 

"Length  of  the  largest  specimen  in  the  collection,  0.63  inch  ;  breadth,  0.50  inch ; 
convexity,  0.34  inch. 

"Locality  and  Position:  Alexander  County,  Illinois,  in  a  thin  local  bed  of 
gray  limestone ;  apparently  near  the  horizon  of  the  Niagara  division  of  the  Upper 
Silurian." 

This  species  is  very  common  in  the  thick  layers  of  gray  limestone 
in  the  upper  part  of  the  Edgewood  strata,  and  is  one  of  the  characteristic 
fossils  of  this  formation  in  Illinois. 

Whitfieldella  ovoides  n.sp. 
(Plate  VII,  figures  13,  14,  and  15) 
1868.     Mcristclla?  sp.     Meek  and  Worthen,  111.  Geol.   Survey,  vol.  3,  p.  354,  pi.  6, 
figures   4a   and   4b. 

Shells  differ  from  Whitfieldella  billingsana  (Meek  and  Worthen)  in 
the  larger  size  and  greater  convexity  of  the  valves,  the  more  elliptical 


ALEXANDRIAN  SERIES  135 

outline,  less  acuminate  beaks,  the  ventral  beak  much  more  strongly 
incurved  over  that  of  the  dorsal  valve,  and  in  the  sinus  of  the  ventral 
valve  extending  from  the  front  nearly  to  the  beak.  The  characters  men- 
tioned above  will  also  serve  to  distinguish  this  species  from  IV  hit  field  ella 
acuminata,  described  on  a  later  page,  and  from  IV.  intermedia  Hall. 

The  shells  are  biconvex,  subelliptical  in  outline,  the  greatest  width 
near  the  middle,  the  anterior  margin  truncate  or  somewhat  produced. 
Ventral  valve  rather  strongly  arched,  most  convex  in  the  umbonal  region 
from  which  the  surface  slopes  abruptly  to  the  cardinal  margins,  and 
more  gently  to  the  sides  and  front ;  median  portion  of  the  shell  depressed 
in  a  narrow  shallow  sinus  which  is  deepest  at  the  front  margin,  from 
which  it  extends  two-thirds  or  more  of  the  distance  to  the  beak;  the  beak 
of  the  ventral  valve  is  prominent,  and  strongly  incurved  over  and  upon 
that  of  the  dorsal  valve.  Dorsal  valve  slightly  less  convex  than  the 
ventral ;  highest  along  the  median  line,  especially  on  the  posterior  half 
of  the  shell,  from  which  the  cardinal  slopes  are  steeper  than  those  over 
the  lateral  and  antero-lateral  portions ;  no  well  defined  mesial  fold  is 
present  but  the  median  portion  of  the  valve  is  the  most  prominent  from 
the  front  to  near  the  beak,  which  is  concealed  beneath  that  of  the  ventral 
valve.  Surface  of  both  valves  marked  by  lines  of  growth  and  by  numer- 
ous very  fine  concentric  striae,  which  appear  only  under  a  lens. 

The  dimensions  are:  length,  18  to  22  mm.;  width,  15  to  17  mm.; 
thickness,  8  to  9  mm. 

This  species  gecurs  in  the  Edgewood  limestone  near  Thebes,  Illinois, 
and  Edgewood,  Missouri.  It  is  common  in  the  upper  layer  of  the  oolite 
at  Louisiana,  and  at  a  corresponding  level  between  Clarksville  and  Kissen- 
ger,  in  Pike  County,  Missouri ;  and  is  also  common  in  the  Channahon 
limestone,  in  Will  County,  Illinois. 

W hit  field ella  f  speciosa  n.sp. 
(Plate  VII,  figures  16  and  17) 
Shell  biconvex,  broadly  subovate  in  outline,  the  length  and  width 
about  equal,  the  greatest  width  a  little  anterior  to  the  middle ;  valves 
subequally  convex.  Ventral  valve  moderately  convex,  most  prominent 
a  little  posterior  to  the  middle,  the  beak  pointed,  not  much  incurved ;  the 
lateral  margins  meeting  at  the  beak  at  an  angle  of  80  to  100  degrees,  the 
cardinal  slopes  abrupt,  lateral  slopes  somewhat  less  steep,  and  the  anter- 
ior slopes  more  gentle ;  the  mesial  portion  of  the  valve  depressed  in  a 
rounded  sinus  extending  nearly  to  the  beak,  widest  in  the  anterior  por- 
tion where  it  is  slightly  produced.  Dorsal  valve  with  the  convexity 
and  surface  slopes  much  as  those  in  the  ventral  valve,  the  beak  pointed 


136  BIENNIAL   REPORT 

but  not  much  incurved,  the  median  portion  elevated  in  a  fold  which  is 
rather  flat  on  top  and  extends  nearly  to  the  beak,  most  prominent  in  the 
anterior  portion,  where  in  some  shells  it  is  rather  definitely  bounded. 
Surface  marked  by  numerous  very  fine  concentric  striae  and  a  few 
stronger  concentric  lines  of  growth,  which  are  usually  confined  to  the 
marginal  portions  of  the  shells. 

The  dimensions  are:  length  10  to  11  mm.;  width,  about  equaling 
the  length ;  thickness,  4  to  5  mm. 

This  species  is  common  in  the  Noix  oolite  member  of  the  Edge- 
wood  limestone  in  the  vicinity  of  Louisiana  and  south  of  Clarksville, 
Missouri,  and  below  Hamburg  in  Calhoun  County,  Illinois. 

Mollusca 

Pelecypoda 

Ctenodonta  subelliptica  n.sp. 

(Plate  VII,  figure  25) 

Shell  somewhat  resembles  Ctenodonta  elliptica  Hall  in  general 
outline,  but  differs  from  that  species  in  the  much  smaller  size,  in  the 
steeper  anterior  slope,  and  in  the  more  narrowly  rounded  posterior 
extremity.  The  shells  are  subelliptical  in  outline,  the  greatest  convex- 
ity above  and  posterior  to  the  center,  slightly  flattened  in  the  umbonal 
regions,  the  anterior  margin  slightly  concave  from  the  beak  to  the  mid- 
dle of  the  front,  thence  rounding  somewhat  sharply  to  the  ventral  mar- 
gin, which  is  rather  uniformly  and  broadly  convex,  to  the  posterior, 
where  it  curves  most  strongly  upward  around  the  posterior  margin  to 
the  hinge ;  the  slope  from  the  beak  to  the  posterior  extremity  is  nearly 
straight.  The  beaks  are  situated  slightly  anterior  to  the  middle,  mod- 
erately prominent,  pointed  forward,  and  slightly  incurved.  Surface 
marked  by  fine  concentric  lines  of  growth  which  are  more  numerous  near 
the  margins. 

The  dimensions  are:  length,  about  13  mm.;  width,  7.5  mm.;  and 
thickness,  about  3  mm. 

This  species  is  very  common  in  the  lower  part  of  the  Edgewood 
limestone  near  Edgewood,  Missouri. 

Ptcrinca  tlicbcscnsis  Meek  and  Worthen 

(Plate  VII,  figure  28) 

1868.     Pterinea  thebesensis.     Meek  and  Worthen,  111.  Geol.   Survey,  vol.  3,  p.  354, 

pi.  6,  figure  3. 

Meek  and  Worthen' s  description:     "Shell    (left  valve)    obliquely  rhombicoval, 

longer  than  high,  moderately  convex  in  the  central  and  umbonal  regions ;  cardinal 

margin  less  than  the  greatest  length,  bordered  behind  by  an  obscure  marginal  ridge, 

and  ranging  very  obliquely  to  the  umbonal  axis,  or  nearly  parallel  to  the  greater 


ALEXANDRIAN  SERIES  137 

diameter  of  the  valve;  basal  margin  forming  a  broad  semicircular  curve;  anterior 
side  truncated,  sometimes  obliquely  and  sometimes  nearly  vertically,  a  little  rounded 
at  its  rectangular  connection  with  the  hinge  above,  rather  distinctly  gaping  (unless 
the  margin  of  the  other  valve  is  warped  inwards)  ;  posterior  margin  most  prom- 
inent, and  narrowly  rounded  below  the  wing ;  posterior  wing  abruptly  flattened 
from  the  swell  of  the  umbo,  rectangular  at  the  extremity,  and  considerably  shorter 
than  the  margin  below,  from  which  it  is  separated  by  a  faint  oblique  sinuosity; 
anterior  wing  a  very  short  inconspicuous,  round,  rather  convex  lobe,  obscurely 
denned  by  a  faint,  oblique  concavity,  extending  down  from  the  anterior  side  of  the 
beak,  which  is  moderately  convex,  depressed,  and  placed  about  half  way  between 
the  middle  and  the  anterior  extremity.  Surface  marked  by  fine  concentric  striae, 
and  near  the  anterior  truncated  (gaping?)  margin,  by  rather  distinct  subimbricating 
marks  of  growth. 

"Length  0.80  inch;  height,  0.50  inch;  convexity  (of  left  valve),  0.20  inch. 

"Locality  and  Position  :  Alexander  County,  Illinois,  in  a  thin  local  bed  of 
gray  limestone ;  apparently  near  the  horizon  of  the  Niagara  division  of  the  Upper 
Silurian." 

This  species  is  common  in  the  Edgewood  strata  of  Alexander 
County,  Illinois,  in  which  rocks  the  type  specimen  was  found.  In  some 
respects  it  resembles  the  species  of  Pterinea  occurring  in  the  limestone 
near  Channahon,  but  differs  from  it  in  the  shorter  and  less  pointed  pos- 
terior wing,  and  in  the  less  abruptly  truncate  anterior  margin. 

Colpomya  abrupta  n.sp. 
(Plate  VII,  figure  27) 

Shells  so  unlike  any  other  known  species  that  comparison  would 
be  of  little  value.  They  are  subrhomboidal  to  subquadrate  in  outline, 
moderately  convex,  the  greatest  convexity  a  little  above  the  middle ; 
hinge  line  straight,  two-thirds  the  length  of  the  shell ;  beaks  somewhat 
elevated,  compressed  and  incurved  over  the  hinge  line,  situated  near  the 
anterior  end  which  is  narrower  than  the  posterior,  and  is  short  and 
rounded ;  the  ventral  margin  gently  convex,  slightly  indented  a  little 
anterior  to  the  middle  by  a  shallow  depression  which  extends  over  the 
slightly  flattened  umbones  obliquely  from  the  beaks  to  the  ventral  mar- 
gin ;  the  ventral  margin  rounding  to  the  posterior  end  which  is  obliquely 
truncated,  forming  an  angle  of  about  112  degrees  with  the  hinge;  cardinal 
slope  somewhat  compressed  and  alate  posteriorly.  Surface  marked  by 
moderately  strong  unequal  concentric  lines  of  growth. 

The  dimensions  are :  length  about  21  mm. ;  width  about  12  mm. ; 
and  thickness  5  to  6  mm. 

This  species  occurs  in  the  lower  part  of  the  Edgewood  limestone 
near  Edgewood,  Missouri. 


138  BIENNIAL  REPORT 

Cypricardinia  subqnadrata  n.sp. 
(Plate  VII,  figure  26) 

Shell  somewhat  resembles  Cypricardinia  arata  Hall,  from  which  it 
differs  in  the  greater  width  in  proportion  to  its  length,  and  the  more 
truncate  posterior  end  which  meets  the  hinge  line  at  a  much  smaller 
angle.  It  is  also  readily  distinguished  from  C.  undulostriata  Hall  by 
the  relatively  greater  width,  more  nearly  vertical  posterior  extremity, 
and  the  absence  of  fine  undulating  concentric  striae.  The  shells  are 
subquadrate  in  outline,  hinge  line  straight,  more  than  two-thirds  of  the 
greatest  length.  Beak  situated  near  the  anterior  margin,  directed  for- 
ward, moderately  prominent  and  incurved ;  the  anterior  end  short,  con- 
cave immediately  below  the  beaks,  rounding  to  the  basal  margin  which 
is  gently  convex,  and  slightly  indented  near  the  middle.  The  postero- 
ventral  extremity  rounded,  above  which  the  margin  is  truncate,  meet- 
ing the  hinge  line  at  an  angle  of  about  102  degrees.  The  surface  is 
most  convex  in  the  antero-dorsal  portion  where  it  rounds  rather  steeply 
to  the  front;  a  shallow  depression  extends  obliquely  over  the  somewhat 
flattened  umbones  from  near  the  beak  to  the  middle  of  the  basal  margin. 
In  the  posterior  portion,  the  cardinal  slope  becomes  very  gently  convex 
or  somewhat  compressed,  and  alate.  Surface  marked  by  prominent 
concentric  lamellae,  of  which  three  to  five  occupy  the  space  of  1  mm. 

The  dimensions  of  the  type  are :  length,  about  13  mm. ;  width,  7.25 
mm. 

This  species  occurs  in  the  oolite  member  of  the  Edgewood  limestone 
near  Louisiana,  Missouri. 

Liospira  cf.  affine  (Foerste) 

(Plate  VIII,  figure  5) 

1885.     Raphistoma  affinis.     Foerste,   Bull.    Sci.  Lab.   Denison  Univ.,  p.  95,  pi.    19, 

figure  18. 
1893.  Raphistoma  affine.  Foerste,  Ohio  Geol.  Survey,  vol.  7,  p.  550,  pi.  26,  figure 
18;  and  pi.  37a,  figures  la,  b  and  c. 
Foerste' s  description:  "Shell  lenticular;  breadth  a  little  more  than  twice  the 
height ;  convexity  moderate  above,  equally  so  below ;  volutions  varying  from  two 
and  a  half  to  three  and  a  half,  with  a  moderate  slope  above,  coincident  with  that 
of  the  spire ;  the  last  volution  sharply  carinate  around  the  periphery,  convex  below, 
being  more  so  at  the  umbilicus  into  which  the  slope  is  abrupt;  suture  distinct, 
forming  a  small  groove  between  the  volutions;  umbilicus  as  wide  as  the  outer 
volution ;  the  last  volution  becoming  transversely  rhomboidal,  the  aperture  itself 
not  being  preserved,  the  breadth  about  three  times  the  height.  Surface  apparently 
smooth. 

"This  species  is  almost  in  every  respect  identical  with  forms  of  Raphistoma 
lenticularis  as  known  to  me  from  the  Lower  Silurian  formations.  It  is  however 
a  much  smaller  shell,  with  less  numerous  volutions,  and  apparently  a  distinct  form. 


ALEXANDRIAN  SERIES  139 

"Breadth  of  largest  specimen,  7  mm.;  height,  3  mm.;  breadth  of  the  end  of 
the  last  volution,  3  mm. ;  height,  1.2  mm. ;  aperture  not  preserved." 

In  volume  VII  of  the  Geological  Survey  of  Ohio  the  following 
addition  is  made  to  the  description  of  this  species : 

"The  transverse  striae  are  close  and  fine ;  from  the  junction  of  each  whorl 
with  the  preceding  one,  the  striae  bend  back  strongly  towards  the  quite  sharp  angle, 
which  is  formed  at  the  middle  of  each  whorl,  laterally.  In  a  general  way  the  striae 
form  an  angle  of  forty-five  degrees  with  the  latter.  In  the  larger  shells  there  is 
commonly  a  very  shallow  depression  on  the  upper  surface  of  the  last  coil,  a  short 
distance  from  its  edge,  which  causes  an  apparent  slight  thickening  of  the  shell 
along  the  edge,  especially  towards  the  aperture.  The  mouth  is  oblique,  facing 
diagonally  downwards  (if  the  apical  end  of  the  spiral  be  placed  at  the  top).  The 
largest  specimen  so  far  found  has  a  greatest  diameter  of  20  mm." 

Shells  referred  to  this  species  are  not  rare  in  the  oolite  phase  of 
the  Edgewood  in  Pike  County,  Missouri,  and  Calhoun  County,  Illinois. 

Hormotoma  tcnera  n.sp. 
(Plate  VIII,  figure  9) 

Shell  small,  elongate,  consisting  of  about  seven  volutions  which 
enlarge  very  gradually  from  the  apex,  the  last  one  not  expanding  much 
more  rapidly  than  the  preceding;  the  height  about  13  mm.;  greatest 
width  about  5  mm.  Volutions  rather  evenly  convex,  without  any  trace 
of  a  peripheral  angulation  or  band.  The  suture  is  moderately  deep  and 
only  slightly  oblique ;  the  aperture  apparently  ovate,  higher  than  wide. 
The  shell  is  so  exfoliated  that  no  traces  of  surface  markings  of  any 
kind  are  preserved. 

The  shells  of  this  species  somewhat  resemble  those  of  Hormotoma? 
subulata  (Conrad),  from  which  they  differ  in  the  much  smaller  size, 
fewer  and  less  oblique  whorls,  and  the  more  shallow  sutures.  The  same 
characters  will  serve  to  distinguish  them  from  Hormotoma  gracilis  Hall, 
of  the  Ordovician  strata. 

Shells  of  this  species  are  rather  common  in  the  Edgewood  limestone 
near  Edgewood,  and  in  the  oolite  at  Louisiana,  Missouri. 

Lophospira  fasciata  n.sp. 

(Plate  VIII,  figures  7  and  8) 
Shell  rather  small,  conical,  a  little  higher  than  the  width  at  the 
base ;  volutions  about  four  or  five,  but  slightly  overlapping  grad- 
ually increasing  in  size  from  the  apex,  cross  section  about  as  high 
as  wide,  the  outer  volution  enlarging  more  rapidly  than  the  preceding; 
aperture  subcircular,  not  much  expanded ;  periphery  rounded  except  as 
the  carinae  impart  to  it  a  subangular  appearance,  with  somewhat  flat- 
tened   intercarinal    spaces;    revolving    carinae    three,    about    equidistant 


140  BIENNIAL   REPORT 

apart,  the  middle  one  slightly  stronger  than  the  outer  ones.  Base  of 
the  shell  rounding  into  a  small  umbilicus.  Surface  marked  by  numer- 
ous fine  transverse  lines  of  growth  which  are  not  much  deflected  in 
passing  over  the  carinae. 

The  dimensions  are:  height  of  spire,  12  to  15  mm.;  width  at  the 
base,  about  10  mm. 

This  species  is  not  rare  in  the  Edgewood  strata  in  Pike  County, 
Missouri.  It  belongs  to  the  Bicincta  section  of  Lophospira,  as  defined 
by  Ulrich30  and  resembles  L.  bicincta  Hall  in  the  number  of  carinae  on 
the  volutions  and  in  the  almost  vertical  direction  of  the  transverse  striae. 
It  is  distinguished  from  Hall's  species  by  the  shorter  spire,  and  the 
absence  of  a  sharp  elevated  line  bordering  either  side  of  the  central 
carina,  from  which  it  is  separated  by  a  shallow  furrow. 

Lophospira  thebesensis  n.sp. 
(Plate  VII,  figure  31) 

This  species  belongs  to  the  Robusta  section  of  Lophospira,  as  de- 
fined by  Ulrich,30  and  seems  to  be  distantly  related  to  L.  Virata  Ulrich, 
from  the  Cincinnatian  beds  of  Ohio,  which  it  somewhat  resembles  in 
size  and  in  the  larger  surface  features.  It  differs  from  that  species 
in  having  only  three  or  four  volutions,  which  are  more  angular  along 
the  peripheral  band  than  in  that  form.  In  our  species  the  peripheral 
band  is  prominent  and  median  in  position.  Upper  slope  of  the  volutions, 
between  the  band  and  the  suture,  divided  near  the  middle  by  a  low  ridge 
on  either  side  of  which  the  surface  is  flattened  or  concave.  A  more 
distinct  revolving  ridge  occurs  about  the  same  distance  below  the  band, 
the  intervening  spaces  also  being  flattened ;  suture  moderately  deep, 
aperture  and  umbilicus  not  well  exposed.  Transverse  lines  of  growth 
fine  and  numerous. 

The  dimensions  are :  height,  22  to  30  mm. ;  width,  about  equaling 
the  height. 

This  species  is  common  in  the  thick  limestone  layer  of  the  Edge- 
wood  formation  near  Thebes,  where  it  is  associated  with  IV  hit  field  ella 
billing sana  and  Ly cilia  thebesensis.  Similar  shells  were  also  found  in 
the  Edgewood  beds,  near  Edgewood  and  at  Louisiana,  Missouri. 

Bellerophon  consimilis  n.sp. 
(Plate  VIII,  figure  2) 
Shell   differing   from   Bellerophon   exiguus,   with   which   it   is   asso- 
ciated,   in    the   generally    larger    size,    the    narrower   volutions,    and   the 
sharper  and  higher  dorsal  carina.     The  two  latter  characters   also  dis- 


'Ulrich,    E.   0.,   Geol.   Survey  of  Minn.,  vol.   3,  part  2,  p.  963. 


ALEXANDRIAN  SERIES  141 

tinguish  this  form  from  Bcllerophon  umbilicus  with  which  it  seems  to 
be   rather  closely  related. 

In  our  shells  only  the  outer  volution  is  visible.  This  increases 
rather  rapidly  in  size,  in  somewhat  triangular  in  cross  section,  not  much 
expanded  at  the  aperture,  and  bears  throughout  its  length  a  sharp  prom- 
inent dorsal  carina,  away  from  which  the  shell  slopes  quite  steeply,  the 
sides  rounding  below  into  the  small  umbilicus.  Surface  markings  not 
known,  as  the  shells  are  all  in  the  form  of  casts ;  the  surface  of  the  casts 
are  smooth,  preserving  no  trace  of  the  lines  of  growth. 

The  dimensions  are :  greatest  diameter,  18  to  22  mm. ;  greatest 
diameter  of  outer  volution,  about  12  mm. 

Shells  of  the  above  species  occur  in  the  Edgewood  strata  in  the 
Missouri  locality,  and  imperfect  shells  of  Bellerophon,  thought  to  rep- 
resent the  same  species,  were  also  found  in  the  Edgewood  formation  in 
Alexander  County,  Illinois,  where  they  were  associated  with  Schucher- 
tella  propinqua  and  Dalmanites  danai. 

Bellerophon  exiguus  Foerste 

(Plate  VIII,  figure  6) 

1855.     Bucania  exigua.     Foerste,  Bull.  Sci.  Lab.  Denison  Univ.,  vol.  1,  p.  99,  pi.  13, 

figures  18a,  b,  c,  d. 
1889.     Bellerophon  (Bucania)  exigua.     Foerste,  Proc.  Boston  Soc.  Nat.  Hist.,  vol. 

24,  p.  288,  pi.  6,  figure  3. 
1893.  Bcllerophon  (Bucania)  exiguus.  Foerste,  Ohio,  Geol.  Survey,  vol.  7,  p.  548, 
pi.  25,  figures  18a,  b;  pi.  31,  figures  18a,  b;  pi.  31,  figure  3;  pi.  37a,  fig- 
ures 2a,  b,  c. 
Foerste's  description  :  "Number  of  volutions  not  known,  the  last  alone  vis- 
ible, increasing  rapidly  in  size,  and  expanding  at  the  aperture ;  the  exact  character 
of  the  aperture  not  known  from  want  of  preservation,  but  is  presumed  to  be  sim- 
ilar to  that  of  B.  bilobatus.  The  outer  volution  rounded  on  the  dorsum  at  its 
origin,  a  mesial  carina  gradually  developing  towards  the  aperture  near  which  it 
becomes  quite  distinct,  in  some  individuals  decidedly  so.  From  this  carina,  the 
sides  slope  evenly  to  the  umbilicus,  which  they  enter  with  a  sudden  curve,  form- 
ing a  low,  indistinct  lateral  carina,  by  the  increase  of  curvature.  Umbilicus  ap- 
parently closed,  the  last  volution  alone  being  visible  in  the  specimens  examined. 
Surface  of  the  cast  smooth,  traces  of  the  original  shell,  however,  seem  to  remain 
in  a  few  spots,  indicating  a  system  of  striae  curving  from  the  mesial  carina  ob- 
liquely backwards,  these  apparently  crossed  by  the  other  striations.  The  usual 
form  of  the  cast,  however,  is  smooth,  the  shell  being  entirely  removed. 

"Measurements,  on  account  of  the  imperfect  preservation  of  the  shell  towards 
the  aperture,  are  of  little  value,  still  the  following  will  serve  to  give  a  general 
idea  of  the  proportions  of  the  shell.  Greatest  diameter  of  the  typical  specimen 
(PI.  13,  figs,  a,  b),  9  mm.;  diameter  at  right  angles  to  this,  6.2  mm.;  diameter  of 
the  last  volution  at  the  point  where  it  becomes  visible,  3.5  mm. ;  broadest  part  of 
volution  preserved,  7  mm.  From  this  they  vary  in  size  from  the  specimens  which 
become  almost  minute  to  some  having  a  greatest  diameter  of  22  mm." 


142  BIENNIAL  REPORT 

In  size,  shape  of  whorls,  and  general  appearance,  our  shells  resem- 
ble those  of  Foerste's  species  described  above.  However,  neither  the 
aperture  nor  the  umbilicus  are  well  exposed,  and  so  the  certain  identifi- 
cation is  not  possible.  Imperfect  casts  are  not  rare  in  the  Edgewood 
strata,  in  Pike  County,  Missouri. 

Straparollus  pumilis  n.sp. 
(Plate  VII,  figure  29) 

Shell  very  small,  depressed,  consisting  of  about  four  and  one-half, 
rather  gradually  enlarging  volutions,  the  last  one  of  which  comprises 
a  little  more  than  one-half  the  width  of  the  shell ;  the  diameter  is  4  to 
4.5  mm.;  and  the  height  1.5  to  2  mm.;  spire  very  low,  less  than  one- 
half  of  the  height  of  the  shell,  the  suture  is  rather  shallow;  umbilicus 
narrow  and  deep.  The  body  volution  is  sub-elliptical  in  cross  section, 
rounded  in  the  peripheral  portion,  above  which  the  surface  is  rather 
uniformly  convex  to  the  suture,  and  shows  a  corresponding  curvature 
below  the  periphery  to  the  edge  of  the  umbilicus,  into  which  the  slope 
is  more  abrupt.    No  surface  markings  of  any  kind  preserved. 

This  species  resembles  Straparollus  (cf.  Oriostoma)  incarinatum 
Foerste,  from  which  it  is  distinguished  by  its  much  smaller  size,  lower 
spire,  and  narrower  umbilicus. 

Shells  of  this  species  are  not  rare  in  the  lower  layers  of  the  Edge- 
wood  limestone,  near  Edgewood,  Missouri. 

Cyclonema  daytoncnsis  Foerste 
(Plate  VIII,  figure  4) 
1893.  Cyclonema  bilix  Foerste,  Ohio  Geol.  Survey,  vol.  7,  p.  551,  pi.  30,  figure  15. 
Foerste's  description :  "The  outer  lip  of  the  aperture  is  sharp.  The  inner 
lip  is  strongly  broadened,  thus  increasing  a  little  the  size  of  the  aperture.  This 
broadened  flange  of  the  lip  meets  the  lower  surface  of  the  shell  with  a  concave 
curvature,  which  is  strongest  towards  its  inner  end  of  attachment  to  the  previous 
whorl ;  here  it  forms  often  a  strong  though  rounded  groove  with  the  slightly  raised 
margin  of  the  shell.  In  other  respects  the  shell  is  very  variable.  In  the  ordinary 
form  the  whorls  are  rounded.  Very  distinct  fine  close  sharp  striae  of  growth 
traverse  the  shell  transversely,  indicating  the  outlines  of  the  aperture  at  various 
stages  of  development.  In  addition  to  these  striae,  transverse  wrinkles  of  moderate 
distinctness  and  having  the  same  general  direction,  also  are  frequently  present. 
The  longitudinal  revolving  striae  are  much  less  closely  placed,  and  at  more  or 
less  regular  intervals  certain  of  these  striae  are  very  strong  and  sharply  elevated, 
forming  the  most  prominent  lines  in  the  exterior  ornamentation  of  the   shell." 

This  shell  was  submitted  to  Dr.  Foerste  who  kindly  compared  it 
with  the  type  specimen,  and  stated :  "It  can  not  be  distinguished,  and 
is  sufficiently  typical  to  serve  as  the  type  of  the  species  itself."  It  occurs 
in  the  Noix  oolite  bed  at  Louisiana,  and  in  the  Edgewood  strata  near 
Edgewood,  Missouri,  and  near  Thebes,  Illinois. 


ALEXANDRIAN  SERIES  143 

Poleumita  bellasculptilis  n.sp. 
(Plate  VIII,  figure  3) 

Shells  somewhat  resembling  Pleurotomaria  cyclonemoides  described 
by  Meek  and  Worthen  from  the  Niagara  limestone,  but  distinguished 
from  that  species  by  their  much  smaller  size,  and  more  angular  volutions, 
which  are  marked  by  relatively  fewer  revolving  lines.  They  also  re- 
semble Trochonema  pauper  Hall,  from  which  they  differ  in  the  more 
angular  volutions,  which  are  more  flattened  on  the  upper  surface,  in 
the  smaller  umbilicus,  and  the  more  angular  aperture. 

The  shell  is  small,  about  12  mm.  in  height,  the  greatest  wTidth  of 
the  body  whorl  about  one-half  the  height  of  the  shell.  Spire  conical, 
apical  angle  about  90  degrees,  whorls  four  to  five,  scarcely  overlapping; 
the  first  one  or  two  small,  the  succeeding  ones,  especially  the  last, 
rather  rapidly  increasing  in  size.  An  angular  carina  separates  the 
upper  slope  from  the  median  and  basal  portion  of  the  whorls.  The 
upper  slope  of  the  body  whorl,  between  the  suture  and  the  carina,  is 
nearly  flat,  becoming  gradually  more  convex  in  the  higher  whorls  which 
are  nearly  circular  in  section.  Below  the  carina  the  surface  is  flat  or 
gradually  rounded,  down  to  the  gently  convex  basal  portion  of  the 
whorls.  The  upper  slope  of  the  volutions  is  marked  by  three  revolving 
ridges,  of  which  the  middle  one  is  the  largest,  and  is  the  only  one  that 
persists  in  the  two  uppermost  whorls.  Below  the  carina  there  are  twelve 
to  fifteen  revolving  ridges  and  furrows  on  the  body  whorl,  only  five  or 
six  of  which  are  visible  on  this  portion  of  the  second  volution,  the  num- 
ber becoming  gradually  fewer  from  the  aperture  toward  the  apex.  No 
transverse  lines  of  growth  preserved ;  aperture  apparently  subovate,  not 
expanded. 

Shells  of  this  species  occur  in  the  Edgewood  strata  in  Pike  County, 
Missouri. 

Holopea  minuta  n.sp. 
(Plate  VII,  figure  30) 

Shell  readily  distinguished  from  any  known  species  by  its  very 
small  size.  The  height  is  about  2.5  mm.,  the  width  about  equal  to  the 
height.  It  consists  of  about  four  and  one-half,  rather  rapidly  enlarging, 
strongly  convex  volutions,  which  are  nearly  circular  in  cross  section,  the 
last  one  not  very  ventricose.  The  umbilicus  is  very  small;  the  suture 
rather  deep,  the  aperture  apparently  almost  circular,  with  a  thin,  reflexed 
inner  lip.     Surface  with  no  distinct  transverse  markings  preserved. 

This  species  occurs  in  the  lower  part  of  the  Edgewood  limestone, 
near  Edgewood,  Missouri. 


144  BIENNIAL   REPORT 

Diaphorostoma  niagarensis  Hall 

(Plate  VIII,  figure  1) 

1852.     Platyostoma  niagarensis.     Hall,  Paleontology  New  York,  vol.  2,  p.  287,  pi.  60, 

figures    la-v. 
1879.     Platyostoma  niagarensis.     Hall,  28th  Rept.  N.  Y.   State  Mus,  p.  175,  pi.  28, 

figures  1-12;  pi.  29,  figures  1-15. 
1881.     Platyostoma   niagarensis.     Hall,    11th    Ann.    Rept.    Indiana    Geol.    and    Nat. 

Hist.,  pi.   29,   figures   1-12,   and  pi.   30,   figures    1-15. 
1889.     Platyostoma   niagarensis.     Nettelroth,    Ky.    Fossil    Shells:     Mem.    Ky.    Geol. 

Survey,  p.   185,  pi.  33,  figure  30. 
Hall's  description :     "Globose ;   volutions  3   or  4 ;   body  whorl  large ;   inflated 
towards   the   aperture   which   was   dilated;    sutures   deep;    spire   depressed    (rarely 
elevated);   shell  thin;   surface  striated  across  the  volutions,  and  in  well  preserved 
specimens   longitudinally   marked   by    filiform   undulating   striae. 

The  spire  appears  to  be  depressed  often  when  the  shell  retains  its  natural 
proportions,  and  at  other  times  from  pressure;  in  a  few  examples  it  is  consid- 
erably elevated.  The  fine  undulating  longitudinal  striae  do  not  always  appear,  and 
sometimes  only  upon  a  portion  of  the  surface,  even  where  there  is  no  appearance 
of  abrasion.  In  other  examples,  they  have  evidently  been  worn  off,  leaving  the 
transverse  striae  well  preserved." 

In  the  specimens  from  the  Edgewood  formation,  both  in  Missouri 
and  Illinois,  the  transverse  striae  are  well  preserved,  but  there  is  little, 
if  any,  trace  of  longitudinal  markings.  The  species  occurs  near  Thebes, 
Illinois,  and  near  Edgewood,  Missouri. 

Arthropoda 

Trilobita 

Isotelus  longaevus  n.sp. 

(Plate  VIII,  figure  15) 

This  species  of  Isotelus  is  especially  interesting  because  it  is  one 
of  the  few  representatives  of  the  genus  that  lingered  for  a  time  after  the 
close  of  the  Ordovician  period.  It  differs  from  the  common  Richmond 
species  Isotelus  maximus  Locke  and  /.  gigas  De  Kay  in  the  proportion- 
ately much  shorter  and  wider  cephalon.  It  most  closely  resembles 
Isotelus  susae  Whitfield  in  its  general  proportions,  but  is  distinguished 
from  that  species  by  its  relatively  broader  and  shorter  cephalon,  by  the 
greater  constriction  of  the  glabella  between  the  eyes,  which  are  not  sit- 
uated so  far  backward  as  in  /.  susae.  The  facial  sutures  behind  the  eyes 
extend  much  farther  outward,  reaching  the  posterior  border  much  nearer 
the  genal  angle  than  in  Whitfield's  species. 

The  cephalon  is  short,  subcrescentiform  in  outline,  the  length  along 
the  median  line  about  12  mm.,  equaling  nearly  one-half  the  greatest 
width ;  the  genal  angles  obtusely  rounded.     The  surface  is  convex  over 


ALEXANDRIAN   SERIES  145 

the  middle  portion,  with  a  rather  abrupt  slope  nearer  the  front  and  lat- 
eral margins.  The  glabella  not  distinctly  defined.  The  eyes  are  sep- 
arated by  a  distance  of  about  one-half  the  length  of  the  cephalon,  situ- 
ated a  little  posterior  to  the  middle  of  the  head.  Anterior  to  the  eyes 
the  facial  sutures  round  outward  to  near  the  margin  which  is  reached 
in  front  of  the  median  line  of  the  eyes,  the  sutures  from  opposite  sides 
are  then  continuous  around  the  anterior  extremity  of  the  cephalon  to 
their  junction  at  the  middle  of  the  front  margin.  Posterior  to  the  eyes 
the  sutures  are  directed  backward  and  outward,  cutting  the  posterior 
border  a  little  more  than  one-half  the  distance  from  a  point  in  the  pos- 
terior border  directly  behind  the  inner  margin  of  the  eyes  to  the  genal 
angles.  The  free  cheeks  are  broad,  gently  convex,  longer  than  wide, 
the  widest  part  being  opposite  the  posterior  border  of  the  eyes ;  the 
outer  border,  behind  the  point  where  the  facial  suture  reaches  the 
anterior  margin,  is  nearly  straight  to  the  obtusely  rounded  genal  angles. 
This  species  occurs  in  the  lower  part  of  the  Edgewood  limestone 
near  Edgewood.  Illinois,  where  it  is  associated  with  Dalmanitcs  danai 
and  Schuchertella  propinqua. 

Pvoctus  determinatus  Foerste 

(Plate  VIII,  figures  10  and  11) 

1885.     Bathyurus.     Foerste,    Bull.    Sci.   Lab.    Denison   Univ.,   vol.    1,   p.    103,   pi.    14, 

figure  5. 
1887.     Proetus  determinatus.     Foerste,  Bull.  Sci.  Lab.  Denison  Univ.,  vol.  2.  p.  91, 

pi.  8,  figures  2,  3,  3a. 
1895.     Proetus   determinatus.     Foerste,    Ohio    Geol.    Survey,   vol.   7,    p.    523,   pi.   26, 

fig.  5 ;  pi.  27,  figures  2,  3,  3a. 
Foerste's  description :  "Glabella  conical,  convex,  sharply  defined  from  the 
remaining  portions  of  the  head  by  a  distinct  furrow ;  obscurely  marked  by  three 
pairs  of  grooves;  the  posterior  pair  being  inclined  at  an  angle  of  forty-five  de- 
grees to  the  axis  of  the  glabella,  cutting  off  the  postero-lateral  corners;  the  mid- 
dle pair,  although  shorter  and  less  inclined,  are  still  fairly  distinct ;  the  anterior 
pair  are  very  indistinct,  quite  short,  and  but  slightly  inclined ;  in  addition  three 
very  indistinct  pairs  of  pits  may  be  seen,  the  two  anterior  pairs  are  at  the  ends 
of  the  two  anterior  pairs  of  grooves,  the  posterior  pair  are  opposite  the  middle 
of  the  posterior  grooves.  In  the  distinct  occipital  furrow  beneath  the  postero- 
lateral corners  of  the  glabella  are  two  almost  triangular  tubercles  which  add  to 
the  conical  appearance  of  the  glabella.  The  occipital  ring,  broad  at  the  middle, 
narrow  at  the  ends,  is  supplied  with  a  distinct  granule  near  the  center. 

"The  anterior  margin  of  the  head  is  curved  downwards,  giving  this  portion 
of  the  head  a  distinctly  convex  appearance ;  the  edge  is  narrow,  but  plainly  ele- 
vated at  an  angle  of  perhaps  forty  degrees  with  those  parts  of  the  anterior  mar- 
gin immediately  adjacent.  The  palpebral  lobes  are  rounded,  and  are  situated 
opposite  the  anterior  half  of  the  posterior  furrows.  The  facial  sutures  anterior 
to  the  palpebral  lobes  curve  slowly  outward  toward  the  anterior  edge,  then  sud- 
denly inward  again,  cutting  the  edge  beyond  a  line  passing  through  the  lateral 
edge  of  the  tubercles. 


146  BIENNIAL  REPORT 

"In  this  genus  the  facial  sutures  behind  the  eyes  are  parallel  for  a  short  dis- 
tance, then  curve  outward  and  reach  the  posterior  border  of  the  head,  usually 
at  a  point  half  way  between  the  glabella  and  the  postero-lateral  margin  of  the 
head.  In  Cyphaspis  the  posterior  furrows  become  deep  grooves,  dividing  the 
glabella  into  three  distinct  lobes,  of  which  the  central  lobe  is  obovate  in  form. 
The  middle  and  anterior  furrows  are  usually  wanting.  The  tubercles  found  in 
the  Ohio  species  have  not  this  signification,  but  are  caused  by  the  bifurcation  of 
the   occipital    furrow. 

"Length  of  smaller  specimen,  glabella,  3.5  mm.;  including  anterior  margin, 
5  mm.  Breadth  of  glabella  3.1  mm. ;  including  palpebral  lobes,  4.5  mm. ;  width 
measured  between  the  antero-lateral  margins  of  the  area  anterior  to  the  glabella, 
4.5  mm.  Length  of  the  larger  specimen,  glabella,  7  mm. ;  including  occipital  ring, 
8.2  mm. ;  including  also  anterior  margin,  10  mm.  Width  of  glabella  just  above 
the  tubercles,  7  mm. 

"Locality  and  Position :     Soldiers  Home,  near  Dayton,  Ohio,  Clinton  Group." 

This  is  a  common  species  in  the  gray  limestone  in  the  upper  part 
of  the  Edgewood  formation,  in  Illinois,  and  in  equivalent  layers  near 
Edgewood  and  at  Louisiana,  Missouri. 

Cyphaspis  intermedia   (Weller) 
(Plate  VIII,  figure  12;  and  Plate  IX,  figure  26) 
For  the  description  of  this  species  refer  to  descriptions  of  fossils  of 
the  Channahon  limestone. 

Cranidia  of  a  trilobite  that  can  not  be  distinguished  from  the  above 
species  are  not  rare  in  the  Edgewood  strata  near  Thebes,  Illinois,  and 
in  Pike  County,  Missouri. 

Metapolichas  breviceps  var.  clintonensis  (Foerste) 
(Plate  VIII,  figures  13  and  14) 
1895.  Lichas  breviceps  var.  clintonensis.  Foerste,  Ohio  Geol.  Survey,  vol.  7,  p.  529„ 
pi.  25,  figures  26a-26e ;  pi.  27,  figures  18,  19. 
Foerste's  description :  "This  species  occurs  in  the  Ohio  Clinton  limestone 
at  Brown's  Quarry,  common  (glabella  sometimes  22  mm.  long)  ;  Soldier's  Home, 
rare ;  Fauver's  Quarry,  a  glabella ;  in  the  'Orthoceras  block'  from  Huffman's 
Quarry ;  upper  shaly  courses  at  Huffman's  Quarry,  several  specimens ;  Fair  Haven,, 
a  glabella;  Hanover,  Indiana,  rare.  A  careful  study  of  the  head  of  the  typical 
forms  of  Lichas  breviceps  from  the  Niagara  of  Waldron,  Indiana,  was  prepared 
for  the  Bulletin  of  Denison  University  vol.  3,  pi.  13,  figure  21.  An  entire  head  was 
found  in  the  above  mentioned  'Orthoceras  block'.  It  presents  all  the  features 
of  the  Waldron  head  with  one  exception.  In  the  occipital  furrow — between  the 
postero-lateral  lobes  of  the  glabella,  the  occipital  segment,  and  the  area  posterior 
to  the  eye — lies,  in  the  case  of  this  as  well  as  all  other  Clinton  specimens,  a  trans- 
versely oblong,  very  distinct,  and  fairly  large  lobe,  represented  in  the  case  of  the 
Waldron  specimens  only  by  a  very  slight  ridge.  When  it  is  desired  to  distinguish 
this  Clinton  form  from  its  Niagara  descendant  the  varietal  name  clintonensis  may 
be  used.  The  Clinton  pygidia  show  no  distinctions.  The  hypostoma  is  frequent 
at  Brown's  Quarry." 


ALEXANDRIAN  SERIES  147 

In  the  cranidium  of  this  trilobite  there  is  present,  in  the  occipital 
furrow  beneath  each  one  of  the  lateral  lobes,  a  distinct  oblong  lobe 
which  is  characteristic  of  Foerste's  variety  clintonensis  of  this  species. 
This  is  a  common  fossil  in  the  heavy  layer  of  gray  limestone  in  the 
upper  part  of  the  Edgewood  formation,  in  Illinois.  It  is  also  found  in 
corresponding  strata  near  Edgewood  and  in  the  Noix  oolite  member  at 
Louisiana*  Missouri. 

Dalmanitcs  danai  Meek  and  Worthen 

(Plate  VIII,  figures  16  and  17) 

1865.     Dalmania  danae.     Meek  and  Worthen,  Proc.  Acad.  Nat.  Sci.,  Philad.,  p.  264. 

1868.     Dalmanites  danae.     Meek  and  Worthen,  111.  Geol.  Survey,  vol.  3,  p.  363,  pi.  6, 

figures  la-lf. 

Meek  and  Worthen's  description :  "Attaining  a  large  size,  entire  outline 
ovate.  Cephalic  shield  rather  compressed,  nearly  semicircular,  about  twice  as 
wide  as  long,  rounded  in  front,  and  nearly  straight  or  slightly  concave  in  outline 
behind,  with  posterior  lateral  angles  produced  into  mucronate  spines  extending 
backwards  to  the  fourth  or  fifth  thoracic  segment.  Glabella  composing  rather 
more  than  one-third  the  entire  area  of  the  shield,  and  slightly  more  convex  than 
the  cheeks,  including  the  neck  segment,  as  long  as  its  greatest  anterior  breadth, 
and  about  twice  as  wide  (exclusive  of  the  alae,  or  fixed  cheeks)  in  front  as  behind; 
separated  from  the  cheeks  on  each  side  by  a  well  defined  furrow ;  anterior  lobe 
composing  about  half  its  entire  area,  transversely  elliptical,  and  a  little  less  than 
twice  as  wide  as  long,  usually  showing  in  internal  casts  a  shallow  pit  near  the 
middle  of  its  posterior  side ;  lateral  furrows  well  defined — anterior  one  oblique, 
the  other  two  transverse,  and  not  always  strongly  defined  quite  out  to  the  lateral 
margins ;  anterior  lateral  lobe  longer,  more  oblique,  and,  at  its  outer  end,  wider 
than  either  of  the  other  two.  Occipital  segment  widest  and  most  prominent  in 
the  middle,  scarcely  equaling  the  transverse  diameter  of  the  posterior  extremity 
of  the  glabella;  neck  furrow  well  defined,  but  deepest  on  each  side,  and  arching 
a  little  forward  in  the  middle ;  its  continuations  across  the  posterior  sides  of  the 
cheeks  broad,  deep,  and  straighter  than  the  posterior  margin — extending  nearly 
to  the  lateral  margins  of  the  cheeks,  where  they  curve  a  little  backwards.  Cheeks 
sloping  slightly  around  the  outer  side  to  a  broad,  shallow  undefined  marginal  de- 
pression, outside  of  which  there  is  a  moderately  thick,  somewhat  rounded  border, 
which  does  not  extend  entirely  around  the  front  of  the  glabella,  but  continues 
back  into  the  posterior  lateral  spines.  Eyes  reniform,  not  oblique,  nearly  half  as 
long  as  the  antero-posterior  diameter  of  the  front  lobe  of  the  glabella,  and  sit- 
uated slightly  more  than  their  own  length  in  advance  of  the  posterior  margin  of 
the  cheeks,  with  (in  casts)  a  moderately  distinct  marginal  furrow  around  their 
outer  bases;  (height  and  other  details  unknown)  ;  palpebral  lobes  semicircular  and 
depressed.  Facial  sutures  cutting  the  lateral  margins  of  the  cheeks  nearly  oppo- 
site the  posterior  extremities  of  the  eyes,  and  passing  around  the  antero-lateral 
and  front  margins  of  the  glabella  so  near  the  anterior  border  as  scarcely  to  leave 
any  perceptible  band  connecting  the  movable  cheeks  around  the  front. 

"Hypostoma  obscurely  subtrigonal,  about  one-eighth  wider  anteriorly  than 
its  length,  moderately  convex ;  anterior  margin  forming  a  broad,  regular,  con- 
vex   curve ;    lateral    margins    contracted    behind    the    anterior    lateral    angles,    and 


148  BIENNIAL   REPORT 

converging  a  little  posteriorly  for  about  two-thirds  the  entire  length,  thence  more 
abruptly  to  the  posterior  extremity,  which  is  transversely  truncated,  and  provided 
on  each  side  with  a  minute,  slightly  projecting  point,  while  still  farther  forward, 
on  each  lateral  margin,  there  appears  to  be  traces  of  another  minute  slightly  pro- 
jecting irregularity  of  outline.  Around  the  posterior  and  lateral  margins  there 
is  a  more  or  less  distinct  sulcus,  behind  which  the  posterior  margin  is  flattened. 
Within  this  marginal  sulcus  there  is,  on  each  side,  a  little  behind  the  middle,  an 
oblique   eye-like   depression. 

"Thorax  wider  than  long,  the  length  being  to  the  breadth  as  21  to  28,  nearly 
once  and  a  half  as  long  as  the  cephalic  shield;  mesial  lobe  as  wide  anteriorly 
as  the  posterior  extremity  of  the  glabella,  and  very  slightly  broader  near  the 
middle,  where  it  is  about  three-fourths  as  wide  as  the  lateral  lobes,  from  which 
it  is  only  separated  by  narrow,  rather  shallow  furrows — most  convex  along  the 
middle  and  flattened  on  each  side ;  segments  not  clearly  seen  in  the  specimens  ex- 
amined. Lateral  lobes  somewhat  more  depressed  than  the  mesial  one,  and  sloping 
very  gradually  to  the  lateral  margins.  Segments  equaling  the  antero-posterior 
diameter  of  the  posterior  lateral  lobes  of  the  glabella;  each  curving  abruptly  back- 
wards at  the  outer  extremity  and  terminating  in  a  flat,  sharply  pointed,  or  lanceo- 
late projection,  most  produced  in  the  posterior  ones;  provided  with  a  deep,  well 
defined,  longitudinal  furrow,  which  starts  from  the  anterior  side  of  the  inner 
end,  and  curves  at  first  a  little  obliquely  outward,  and  then  passes  straight  out- 
ward, slightly  nearer  the  posterior  than  the  anterior  margin,  to  the  middle  of 
the  flattened  scythe-shaped  outer  ends,  where  they  usually  curve  a  little  backwards 
and    become   obsolete. 

"Pygidium  nearly  semielliptic,  or  subtrigonal,  the  anterior  lateral  angles  be- 
ing somewhat  rounded,  and  the  lateral  margins  converging  to  the  more  or  less 
pointed  posterior  extremity,  with  a  broad  convex  curve ;  slightly  longer  than  the 
cephalic  shield,  and  rather  more  than  two-thirds  as  wide ;  mesial  lobe  somewhat 
more  convex  than  the  lateral  lobes,  and  two-thirds  as  wide,  gently  rounded,  and 
tapering  gradually  to  the  posterior  extremity  where  it  is  apparently  continued 
into  an  abruptly  projecting  caudal  appendage;  segments  12  to  13,  straight,  well 
defined  (except  near  the  termination)  by  distinct  furrows,  which  are  deeper  on 
each  side  than  at  the  middle.  Lateral  lobes  with  eight  or  nine  well  defined  arched 
segments,  which  become  more  oblique  posteriorly,  and  are  defined  to  near  the 
edge  of  the  smooth  margin ;  each  divided  by  a  furrow  deeper  than  those  between, 
and  like  in  those  of  the  pleurae,  the  anterior  division  being  slightly  narrower  than 
the  other  at  the  inner  end. 

"Surface  (of  cast)  smooth,  except  traces  of  small  scattering  tubercles  on 
the   anterior  lobe  of   the   glabella. 

"Length  of  the  largest  specimen  seen,  exclusive  of  the  little  caudal  append- 
age (the  length  of  which  is  unknown),  4.93  inches.  Length  of  pygidium,  1.50 
inches ;  breadth  of  same,  2  inches ;  breadth  of  its  axillary  lobe,  0.55  inch.  Length 
of  thorax,  2.05  inches;  breadth  of  same,  3  inches;  breadth  of  its  mesial  lobe,  0.80 
inch.  Length  of  cephalic  shield,  1.44  inches;  breadth  of  same,  3  inches;  length 
of  posterior  lateral  spines,  near  1.10  inches;  length  of  glabella,  exclusive  of  neck 
segment,  1.30  inches ;  anterior  breadth  of  same,  1.35  inches ;  posterior  breadth 
of  same,  0.84  inch.  Length  of  eyes,  0.39  inch ;  distance  of  same  from  posterior 
margin  of  cheeks,  0.42  inch. 


ALEXANDRIAN  SERIES  149 

"Locality  and  position :  Two  miles  above  Thebes,  Alexander  County,  Illi- 
nois. Apparently  at  or  near  the  horizon  of  the  Niagara  division  of  the  Upper 
Silurian." 

This  trilobite  is  very  abundant  in  a  narrow,  somewhat  shaly  zone 
in  the  lower  part  of  the  Edgewood  beds,  near  Thebes,  Illinois,  and  in 
the  lower  layers  of  this  formation  near  Edgewood,  Missouri.  It  resem- 
bles D.  limulurus  (Green),  in  some  respects,  but  may  be  distinguished 
from  that  species  in  its  larger  size,  its  more  obtusely  rounded  anterior 
margin  of  the  cephalon,  the  more  convex  outline  of  the  lateral  margins 
of  pygidium,  the  fewer  number  of  annulations  in  the  axis  of  the  pygid- 
ium,  and  in  the  shorter  and  more  slender  caudal  spine. 

Fossils. from  Channahon  Limestone  Members 

Coelenterata 

Anthozoa 

Zaphrentis  ambigua  n.sp. 

(Plate  IX,  figure  2) 

Corallum  resembling  Z.  subregularis  in  having  the  longitudinal 
(septal)  striae  distinctly  visible  on  the  exterior,  and  crossed  by  very  fine 
transverse  lines  ;  in  the  alternating  curved  septa  which  do  not  reach  the 
center,  and  are  united  at  their  inner  ends  into  sets  of  twos  and  threes. 
It  differs  from  that  species  in  the  longer,  more  slender  and  gently  taper- 
ing, and  variously  flexed  mode  of  growth,  and  in  having  the  surface 
marked  with  frequent  prominent  transverse  ridges  and  constrictions 
throughout  its  length.  Septa  alternating  in  size,  primary  septa  forty 
to  fifty,  undulating,  fasciculate,  the  inner  edges  of  the  bundles  extend- 
ing more  than  half  way  to  the  center,  secondary  septa  very  short,  dis- 
tinct only  in  the  calyx,  tabulae  somewhat  irregular,  nearly  horizontal 
for  about  one-third  of  the  diameter  of  the  corallum.  Calyx  of  individ- 
uals of  average  size,  about  12  to  15  mm.  deep,  with  thin  walls  and  steep 
slope;  diameter  about  11  mm.  when  the  length  of  the  corallum  is  40  mm. 
Surface  marked  by  distinct  longitudinal  septal  striae  and  by  numerous 
ridges  and  furrows  of  unequal  size,  which  are  covered  by  numerous 
very  fine  transverse  lines. 

The  dimensions  are:    length,  25  to  80  mm.;  diameter,  8  to  13  mm. 

This  species  is  common  in  the  lower  part  of  the  Channahon  lime- 
stone in  Will  County,  Illinois,  where  it  is  associated  with  Zaphrentis 
subregularis,  Schuchcrtella  curvistriata,  Metapoliclias  ferrisi  and  other 
fossils  of  this  limestone.  Coralla  thought  to  represent  this  species  are 
also  common  in  the  Edgewood  limestone  near  Edgewood,  and  in  the 
Noix  oolite  member  of  this  formation  at  Louisiana,  near  the  mouth  of 
Buffalo  Creek,  and  south  of  Clarksville,  Missouri. 


150  BIENNIAL  REPORT 

Zaphrcntis  subregidaris  n.sp. 
(Plate  IX,  figure  1) 

For  the  description  of  this  species  see  a  previous  page  of  this  paper. 
Coralla  referred  to  this  species  are  numerous  in  the  Channahon  limestone 
in  Will  County,  Illinois. 

Molluscoidea 

Brachiopoda 

Lingulops  illinoisensis  n.sp. 

(Plate  IX,  figures  3  and  4) 

Shells  resemble  Lingulops  granti  Hall  and  Clarke,  of  the  Niagaran 
in  their  subelliptical  to  obovate  outline,  in  the  platform-like  muscular 
area  of  the  valves,  in  the  absence  of  the  median  septum  in  the  ventral 
valve,  and  in  the  broad  margin  of  contact  around  the  peripheral  portion 
of  the  shells,  which  is  grooved  for  the  passage  of  the  pedicle.  They 
differ  from  L.  granti  in  their  uniformly  much  smaller  size,  more  obovate 
outline  (some  of  the  shells  are  more  strongly  obovate  than  those  fig- 
ured), and  the  more  tapering  anterior  portion.  The  posterior  extrem- 
ity is  slightly  less  acuminate  than  in  L.  granti;  the  peripheral  margin 
of  contact  is  broader  than  in  that  species,  and  has  not  its  greatest  width 
beneath  the  beak  of  the  ventral  valve.  The  muscular  platform  in  the 
ventral  valve  is  somewhat  wider  and  presents  a  more  distinctly  lobate 
appearance  than  in  shells  of  the  above  named  Niagaran  species,  appar- 
ently consisting  of  two  median  lobes  extending  nearly  one-half  the  dis- 
tance to  the  anterior  margin,  on  each  side  of  these  are  two  or  three 
lateral  lobes  the  outer  ones  of  which  are  successively  shorter.  The 
exterior  surface  of  the  valves  was  not  seen. 

The  dimensions  are :    length,  2.5  to  3  mm. ;  width,  about  2  mm. 

Shells  of  this  species  are  common  in  the  Channahon  limestone  in 
Will  County,  Illinois,  where  they  are  associated  with  Cyphaspis  inter- 
media, Proctus  channahonensis  and  other  species  characteristic  of  this 
limestone. 

Pholidops  sub  elliptic  a  n.sp. 
(Plate  IX,  figure  5) 

Shell  somewhat  resembles  the  Niagaran  species,  Pholidops  squami- 
formis  Hall,  from  which  it  is  distinguished  by  its  less  quadrate,  and 
more  elliptical  to  ovate  outline,  and  by  the  absence  of  any  trace  of 
radiating  striae.  It  also  differs  from  P.  ovalis  Hall  in  the  relatively 
narrower  posterior  portion,  and  in  having  the  apex  situated  nearer  the 
posterior  margin. 

The  shell  of  P.  snbclliptica  is  depressed  convex  or  almost  flat,  sub- 
ovate  to   subelliptical   in   outline,   about  three-fourths   as   wide  as   long, 


ALEXANDRIAN  SERIES  151 

widest  at  or  anterior  to  the  middle ;  the  apex  pointed  and  situated  about 
.5  mm.  from  the  posterior  margin.  Surface  marked  by  strong  concen- 
tric lamellae,  with  no  trace  of  radiating  markings. 

The  dimensions  are :  length,  about  4.5  mm. ;  and  width,  about  3.5 
mm. 

This  species  is  rare  in  the  Channahon  limestone  in  Will  County, 
Illinois,  where  it  is  associated  with  Lingulops  illinoisensis,  Rhynchotreta 
intermedia  and  other  Channahon  forms. 

Schuchcrtella  curvistriata  n.sp. 
(Plate  IX,  figure  6) 

This  species  was  probably  derived  from  5.  missouriensis  Shumard, 
of  the  Girardeau  limestone,  which  it  resembles  in  the  nearly  flat  shell; 
in  the  unequal  and  somewhat  fasciculate  character  of  the  radiating  striae ; 
in  the  distinct  upward  curving  of  the  striae  in  the  cardino-lateral  re- 
gions ;  and  in  the  numerous,  very  fine  concentric  markings  which  are 
somewhat  undulating  as  they  cross  the  wide,  flat  spaces  between  the 
larger  radiating  striae.  It  differs  from  that  species  in  the  larger  size, 
and  the  greater  length  in  proportion  to  the  width  of  the  shell.  The 
primary  radiating  striae  extend  to  the  beak  and  are  twelve  to  sixteen  in 
number;  between  any  two  of  these  there  are  usually  intercalated  three 
rather  coarse  lines,  the  longest  one  of  which  extends  nearly  to  the  beak, 
the  one  of  intermediate  length  reaches  considerably  posterior  to  the 
middle  of  the  valve,  while  the  shortest  one  is  not  conspicuous  more  than 
one-third  of  the  distance  from  the  margins. 

This  species  also  somewhat  resembles  S.  propiuqua  of  the  Edge- 
wood  strata,  in  size  and  general  appearance,  but  can  be  distinguished 
from  it  by  the  upward  curving  of  the  radiating  striae  in  the  cardino- 
lateral  regions,  and  in  the  generally  shorter  hinge  line  in  proportion  to 
the  greatest  width  of  the  shell,  giving  it  a  more  circular  outline. 

The  dimensions  are:   length,  15  to  22  mm.;  width,  22  to  28  mm. 

Shells  of  this  species  are  very  abundant  in  the  limestone  exposed 
near  Channahon,  in  Will  County,  where  they  are  associated  with  Mcta- 
polichas  ferrisi,  Pterinca  elegans  and  Zaphrentis  ambigua. 

Dalmanella  cf.  edgewoodensis  n.sp. 
(Plate  IX,  figure  9;  and  Plate  VI,  figures  11,  12,  and  13) 
For  description  refer  to  the  descriptions  of  the  fossils  of  the  Edge- 
wood  formation. 

The  shells  of  Dalmanella  from  the  Channahon  limestone  are 
slightly  more  arcuate,  and  have  somewhat  more  angular  plications  than 
those  referred  to  this  species  from  the  Edgewood  strata  of  Missouri. 
They  are  common  in  the  Channahon  limestone  in  Will  County,  Illinois. 


152  BIENNIAL   REPORT 

Rhipidomella  hybrida  (Sowerby) 

(Plate  IX,  figure  10) 

1839.     Orthis    hybrida.     Sowerby,    Murchison's    Silurian    System,    p.    360,    pi.    13, 

figure    11. 
1843.     Orthis  hybrida,     Hall,   Geol.  of  N.  Y.,  Rept.  Fourth  Dist.,  p.   105,  figure  7. 
1852.     Orthis  hybrida.     Hall,   Pal.  N.  Y.,  vol.  2,  p.  253,  pi.  52,  figure  4. 
1860.     Orthis  hybrida.     Roemer.     Die    Silurische    Fauna    des    West.     Tenn.,    p.    63, 

pi.   5,   figure  6. 
1868.     Orthis  hybrida.     Meek  and  Worthen,  111.  Geol.  Survey,  p.  371,  pi.  7,  figure  7. 
1889.     Orthis  hybrida.     Nettelroth,  Kentucky  Fossil  Shells:     Mem.  Ky.  Geol.  Surv., 

p.  39,  pi.  32,  figures  32-35. 
1892.     Rhipidomella   hybrida.     Hall  and   Clarke,   Pal.    N.   Y.  vol.   8,  pt.    1,  pp.  210, 

224,  pi.  6,  figures  1-5. 
1895.     Orthis   (Rhipidomella)    hybrida.     Foerste,   Geol.   Ohio,  vol.  7,  p.  584,  pi.  25, 

figure    10. 

Shell  subcircular  in  outline,  slightly  wider  than  long,  hinge  line  less 
than  two-thirds  as  long  as  the  greatest  width  of  the  shell,  valves  sub- 
equally  convex.  Ventral  valve  moderately  convex,  the  greatest  depth 
in  the  umbonal  region  which  slopes  rather  steeply  to  the  sides ;  beak 
elevated,  somewhat  arched  but  not  incurved  beyond  the  hinge  line,  cardi- 
nal area  narrow,  triangular.  Dorsal  valve  a  little  less  convex  than  the 
ventral,  most  prominent  in  the  umbonal  region  which  is  flat  or  with  a 
slight  depression  in  the  middle  portion ;  cardinal  area  narrower,  and 
beak  lower  and  less  arched  than  in  the  ventral  valve.  Surface  of  both 
valves  marked  by  rather  fine  radiating  striae  which  divide  two  or  three 
times  between  the  beak  and  the  margins,  and  arch  upward  on  the  pos- 
tero-lateral  slopes.  Sometimes  a  few  rather  prominent  concentric  lines 
are  also  present. 

The  dimensions  are:  length,  7.5  to  11  mm.;  width,  9  to  12  mm.; 
thickness,  1.5  to  3  mm. 

The  surface  characters  of  this  species  resemble  those  of  Dalman- 
ella  elegantula  (Dalman),  but  the  shell  is  distinguished  by  the  nearly 
equal  size  and  convexity  of  the  valves,  and  the  absence  of  a  well  defined 
sinus  in  the  dorsal  valve.  It  occurs  in  the  Channahon  limestone,  in 
Will  County,  Illinois. 

Rhynchotreta   lepida   n.sp. 

(Plate  IX,  figures   16  and  17) 

Shell    small,    triangular    in    outline,    valves    subequally    convex,    the 

greatest   width   near   the    front.      Ventral   valve   rather   strongly   convex 

in  the  umbonal  region,  becoming  very  gently  sloping  in   front,  without 

fold  or  sinus ;  beak  large,  elevated,  not  much  incurved.     Dorsal  valve 


ALEXANDRIAN  SERIES  153 

highest  near  the  umbo,  the  slope  becoming  gentle  in  the  anterior  por- 
tion, flattened  or  very  slightly  depressed  in  the  median  umbonal  area, 
the  depression  sometimes  continuing  as  an  undefined  sinus  from  the 
beak  to  the  front;  beak  strong,  much  incurved  beneath  that  of  the 
ventral  valve.  Surface  of  each  valve  marked  by  about  fifteen  simple, 
rounded  plications,  having  rather  wide,  flat  or  gently  rounded  furrows 
between  them ;  numerous  delicate  concentric  markings  and  occasional 
stronger  lines  of  growth  are  usually  present. 

The  dimensions  are :  length,  6  mm. ;  width,  5.5  mm. ;  thickness,  2.5 
mm. 

This  species  resembles  Rhynchotrcta  parva  of  the  Edgewood  lime- 
stone in  its  small  size,  but  differs  from  that  form  in  the  smaller  size  of 
the  adult  shells,  the  larger  apical  angle,  the  more  rounded  plications  and 
the  presence  of  numerous  fine  concentric  markings.  From  R.  simplex 
Foerste  it  may  be  distinguished  by  its  smaller  size,  the  greater  number 
of  plications,  and  the  less  flaring  and  more  truncate  anterior  margin. 
Shells  of  this  species  are  not  rare  in  the  Channahon  limestone  in  Will 
County,  Illinois. 

RJiynchotreta    intermedia   n.sp. 
(Plate  IX,  figures   14  and  15) 

Shells  differing  from  RJiynchotreta  thebesensis  Foerste  in  the 
smaller  size,  more  transverse  shape,  more  prominent  fold  and  sinus  and 
less  elevated  ventral  beak.  It  is  subtriangular  in  outline,  as  wide  or  wider 
than  long,  with  apical  angle  about  ninety  degrees.  Ventral  valve  depressed 
convex  in  the  umbonal  region,  with  a  rather  broad,  shallow  sinus,  which 
widens  toward  the  front,  occupying  the  median  portion  throughout  the 
anterior  two-thirds  of  the  length.  The  lateral  surface  on  either  side  of 
the  sinus  is  almost  flat.  Beak  acute,  elevated,  little  or  not  at  all  incurved. 
Dorsal  valve  rather  evenly  convex,  with  steep  cardino-lateral  slopes  on 
either  side  of  the  beak,  somewhat  flattened  in  the  medium  portion,  an 
ill-defined,  almost  imperceptible  fold  is  present  on  the  anterior  half  of 
the  median  portion  of  the  shell ;  beak  acuminate  and  incurved.  Surface 
of  each  valve  marked  by  about  fourteen  simple,  subangular,  radiating 
plications,  and  occasional  prominent  concentric  lines  of  growth. 

The  dimensions  are:  length,  13  mm.;  width,  14  mm.;  greatest 
thickness,  6  mm. 

This  species  is  rare  in  the  Channahon  limestone  in  Will  County, 
Illinois. 


154  BIENNIAL   REPORT 

A  try  pat  sp. 
(Plate   IX,  figures   7  and  8) 
Separated  valves  of  shells  thought  to  belong  to  a  species  of  Atrypa 
occur  in  the  Channahon  limestone  member  of  the  Edge  wood  near  Chan- 
nahon, in  Will  County,  Illinois. 

Whit  field  ella  acuminata  n.sp. 
(Plate  IX,  figures   11   and   12) 

Shells  resembling  Whit  field  ell  a  billingsana  in  the  subovate  form, 
and  erect,  pointed  beaks,  but  distinguished  from  that  species  in  the  larger 
size  and  much  less  strong  convexity,  and  in  the  produced  anterior  mar- 
gin. The  new  species  is  somewhat  ovate  in  outline,  greatest  width  near 
the  middle,  valves  almost  equally  convex,  posterior  end  acuminate, 
apical  angle  of  larger  shells  nearly  ninety  degrees.  Ventral  valve  mod- 
erately convex,  most  prominent  in  the  umbonal  region,  the  postero-lateral 
slopes  abrupt,  the  convexity  over  the  other  portions  of  the  valve  nearly 
uniform,  a  poorly  defined  mesial  sinus  is  present  for  a  short  distance 
from  the  anterior  margin  where  the  shell  is  slightly  extended;  beak 
acute,  elevated  and  considerably  incurved.  Dorsal  valve  slightly  less 
convex  than  the  ventral,  greatest  convexity  along  the  median  portion 
where  a  low  indistinct  fold  appears  towards  the  front  margin ;  beak 
acute,  incurved  beneath  that  of  the  ventral  valve.  Surface  without 
radiating  ornamentation  ;  but  marked  by  numerous  concentric  lines  which 
are  most  prominent  near  the  margins. 

The  dimensions  are :  length,  about  20  mm. ;  width,  about  14  mm. ; 
thickness,  8  to  9  mm. 

This  species  is  not  rare  in  the  Channahon  limestone,  in  Will  County, 
Illinois,  where  it  is  associated  with  Zaphrentis  ambigua,  Schnchertella 
cnrvistriata  and  Pterinea  elegans. 

Whitfieldella   ovoidcs  n.sp. 
(Plate  IX,  figure  13,  and  Plate  VII,  figures  13,  14,  and  15) 
This  species  is  described  on  an  earlier  page.     It  is  rather  common 
in  the  Channahon  limestone  in  Will  County,  Illinois. 

Mollusca 
Pelecypoda 

Pterinea  elegans  n.sp. 

(Plate  IX,  figure  18) 

This   species  resembles  P.   tJiebesensis  Meek  and  Worthen  in   size 

and  absence  of   radiating  markings,   but  differs   from  that   form  in   its 

less   oblique   shape,   in   the   absence   of   a   marginal   ridge   bordering  the 


ALEXANDRIAN  SERIES  155 

posterior  cardinal  margin,  and  in  the  shorter  and  less  narrowly  rounded 
extension  below  the  posterior  wing.  The  straight  hinge  line  is  a  little 
longer  than  the  greatest  width  of  the  shell  below,  prolonged  posteriorly 
into  a  mucronate  point ;  below  this  the  nearly  straight  posterior  margin 
of  the  wing  rounds  gently  into  the  broadly  curved  basal  margin.  Anter- 
ior side  somewhat  obliquely  truncated,  a  little  rounded  to  the  hinge 
above  and  slightly  gaping.  Posterior  wing  less  abruptly  flattened  from 
the  swell  of  the  umbo  than  in  P.  thcbesensis,  and  separated  from  the 
margin  below  by  only  a  trace  of  a  sinuosity,  which  is  present  only  in 
the  right  valve.  Anterior  wing  short  and  convex  and  somewhat  rounded 
as  in  P.  thebcsensis,  obscurely  defined  by  a  faint  furrow  extending  along 
the  anterior  side  of  the  moderately  convex  beak  which  is  placed  about 
half  way  between  the  middle  and  the  anterior  extremity.  Surface 
marked  by  fine  and  coarser  concentric  lines. 

The  dimensions  are  :  length,  12  to  17  mm. ;  height,  7  to  12  mm. ; 
convexity,  4  to  6  mm. 

This  species  is  abundant  in  the  Channahon  limestone  in  Will 
County,  where  it  is  associated  with  Schuchertella  curvistriata  and  Meta- 
polichas  ferrisi. 

Callonema  pristina  n.sp. 
(Plate  IX,  figure  20) 
Shell  turbinate,  wider  than  high,  consisting  of  about  four  volutions 
which  increases  rather  rapidly  in  size.  The  height  is  about  11  mm.,  and 
the  width  about  14  mm.  The  whorls  are  contiguous  so  that  each  extends 
about  one-half  of  its  height  above  the  preceding  one.  They  are  sub- 
circular  in  cross  section,  wTith  a  very  slight  peripheral  angulation  or 
carina,  above  which  the  volutions  are  very  slightly  flattened.  The  body 
whorl  comprises  more  than  one-half  of  the  height  and  is  about  twice 
the  width  of  the  spire  above.  It  has  a  faint  angulation  along  the  per- 
iphery, above  which  the  slope  is  a  little  less  convex  than  that  from  the 
periphery  to  the  umbilical  region.  The  suture  is  rather  deep.  The 
aperture  is  nearly  circular,  slightly  wider  than  high.  The  umbilicus  is 
very  small  or  closed  by  the  inner  lip  of  the  aperture.  Surface  with 
numerous  simple,  regular,  prominent  transverse  striae,  numbering  about 
six  in  a  distance  of  1  mm.,  which  extend  slightly  backward  from  the 
suture  and  are  scarcely  deflected  in  passing  over  the  periphery  of  the 
volutions,  below  which  they  are  equally  strong  as  above,  and  continue 
obliquely  backward  to  the  umbilical  region.  No  revolving  lines  are  vis- 
ible. This  shell  resembles  no  other  known  Silurian  species  of  gastropods 
with  which  it  should  be  compared.     It  differs  from  Isonemia  in  the  less 


156  BIENNIAL   REPORT 

strong   peripheral   carina,   and    in   having   the   transverse   striae   equally 
strong  below  the  peripheral  angulation  as  above. 

This  species  occurs  in  the  Channahon  limestone  member  of  the 
Edgewood  formation,  near  Channahon,  in  Will  County,  Illinois. 

Cyclonema  daytoncnsis  Foerste 

(Plate  IX,  figure  21) 

For  the  description  of  this  species  see  an  earlier  page.     This  species 

occurs  in  the  upper  part  of  the  Channahon  limestone,  in  Will  County, 

Illinois,  and  in  the  Edgewood  limestone  in  Pike  County,  Missouri,  and 

Alexander  County,  Illinois. 

Diaphorostoma  UUnoisensis  n.sp. 
(Plate  IX,  figure  19) 

Shell  small,  5  to  7  mm.  high,  the  width  about  equaling  the  height. 
The  spire  rising  one-third  of  its  height  above  the  outer  volution,  con- 
sisting of  about  three  whorls  which  expand  quite  rapidly.  The  volutions 
subelliptical  to  subcircular  in  cross  section,  the  vertical  diameter  slightly 
greater  than  the  transverse,  narrowly  rounded  above  so  as  to  form  a 
deeply  impressed  suture,  and  almost  as  abruptly  rounded  on  the  lower 
side.  Aperture  not  expanded,  only  slightly  oblique,  complete,  sub-ellip- 
tical in  outline.  Entire  surface  marked  by  fine  transverse  lines,  and 
occasional  coarser  striae,  which  pass  straight  across  the  volutions  in  an 
almost  vertical  direction. 

The  dimensions  are :  height  of  spire,  5  to  7  mm. ;  greatest  diameter 
of  shell,  5  to  7  mm. 

This  species  is  not  rare  in  the  Channahon  limestone  in  Will  County, 
Illinois.  It  resembles  D.  niagarensis  var.  immatura  in  its  small  size 
and  general  appearance,  but  differs  from  that  form  in  the  more  nearly 
equal  width  and  height  of  the  spire,  and  the  more  nearly  circular  cross 
section  of  the  volutions. 

Cephalopoda 
Dawsonoceras  tenuilineatum  n.sp. 

(Plate  IX,  figure  22) 

This  species  differs  from  Dawsonoceras  annulatum  Sowerby,  of  the 
Niagaran  limestone,  in  having  the  slopes  of  the  annulations  subequal, 
and  the  furrows  or  interspaces  symmetrical,  and  in  having  the  surface 
marked  with  very  fine,  somewhat  undulating  longitudinal  striae  (about 
ten  in  a  width  of  1  mm.)  crossing  the  ridges  and  furrows. 

Shell  moderately  large,  gradually  expanding,  with  prominent  an- 
nulations, of  which  five  occur  in  a  distance  of  25  mm.  where  the  largest 
diameter  of  the  shell  is  one  inch.     The  ridges  and  intervening  furrows 


ALEXANDRIAN  SERIES  157 

are  symmetrical,  marked  by  unequal  transverse  striae  some  of  which 
are  subimbricating.  Very  fine  undulating,  longitudinal  lines  cover  the 
entire  surface. 

This  species  is  common  in  the  Channahon  limestone,  in  Will  County, 
Illinois,  and  specimens  that  are  thought  to  represent  this  species  were 
also  found  in  the  Edgewood  strata  in  Pike  County,  Missouri. 

Arthropoda 

Trilobita 

Proetus  channahonensis  Weller 

(Plate  IX,  figure  25) 

1907.     Proetus  channahonensis.     Weller.  Bull.  Chicago  Acad,  of  Sci.,  No.  4,  pt.  2, 

p.  228,  pi.  20,   figures  6,   7. 

Weller's  description  :  "Head  moderately  convex,  semi-circular  in  outline,  the 
length  of  the  genal  spines  not  determined.  Glabella  semi-elliptical  in  outline,  de- 
pressed convex,  defined  by  distinct  but  not  deep  dorsal  furrows ;  first  and  second 
lateral  furrows  obsolete  or  faint,  nearly  transverse  in  direction  and  not  contin- 
uous across  the  median  portion  of  the  glabella,  posterior  furrows  not  deeply  im- 
pressed but  always  present,  they  originate  at  the  dorsal  furrows  opposite  the 
eyes  and  extend  obliquely  inward  and  backward  with  a  slight  convex  curve  nearly 
to  the  occipital  furrow,  their  posterior  extremities  dividing  the  glabella  into 
three  nearly  equal  parts.  Occipital  furrow  narrow,  well  defined,  including  a  pair 
of  small  subovate  occipital  lobes  back  of  the  postero-lateral  angles  of  the  glabella. 
Occipital  segment  rather  narrow,  its  surface  somewhat  depressed  below  the  gla- 
bella. Surface  of  the  cheeks  sloping  with  an  even  convex  curve  from  the  dorsal 
furrows  laterally  and  anteriorly  to  within  about  one  millimeter  of  the  margin, 
outside  this  convex  slope  is  an  even,  flattened,  continuous  marginal  border  which 
continues  around  the  anterior  margin  of  the  head ;  along  the  posterior  margin 
of  each  cheek  is  a  strong  posterior  cheek  furrow  which  is  continuous  from  the 
dorsal  furrow  opposite  the  occipital  furrow  to  the  inner  side  of  the  marginal 
border.  The  anterior  extremity  of  the  glabella  is  separated  from  the  marginal 
border  by  a  narrow  band  which  is  continuous  with  the  convex  portion  of  the 
cheeks  on  either  side.  The  fixed  cheeks  are  narrow  with  the  palpebral  lobes  rising 
directly  from  the  dorsal  furrows.  Free  cheeks  broad,  the  eyes  of  moderate  size, 
their  surface  describing  about  a  semi-circle,  their  anterior  extremities  at  about 
the  mid-length  of  the  glabella. 

"Pygidium  semi-elliptical  in  outline,  the  axis  strongly  convex,  bordered  by 
the  sharp  dorsal  furrows,  occupying  nearly  one-third  the  entire  width  of  the 
pygidium  at  the  anterior  margin,  tapering  posteriorly  and  terminating  in  a  bluntly 
rounded  extremity  lying  within  the  marginal  border,  divided  into  ten  or  eleven 
rounded  annulations  which  become  faint  posteriorly.  Surface  of  the  pleura 
slightly  flattened  adjacent  to  the  dorsal  furrows  and  then  becoming  moderately 
convex  to  the  lateral  margins,  the  thickened  marginal  border  narrow  and  scarcely 
differentiated  from  the  general  surface,  becoming  a  little  wider  posteriorly ;  each 
slope  is  divided  into  nine  segments  which  become  faint  posteriorly,  the  last  two 
being    scarcely    recognizable,    the    anterior-most    segments    extend    entirely    to    the 


158  BIENNIAL   REPORT 

lateral  margin  but  the  posterior  ones  terminate  within  the  margin,  in  some  speci- 
mens the  broader  segments  are  faintly  grooved  but  in  others  no  grooves  can  be 
detected. 

"The  surface  of  both  head  and  pygidium  are  smooth. 

"The  dimensions  of  a  nearly  complete  head  with  the  exception  of  the  genal 
spines  and  occipital  segment  are :  width  15 :5  mm. ;  length,  along  median  line 
9  mm. ;  width  of  glabella  at  occipital  furrow  6.5  mm.  The  dimensions  of  a  very 
perfect  pygidium  are  :  width  10  mm. ;  length  6.5  mm. ;  width  of  axis  at  anterior 
margin  3  mm. ;  length  of  axis  5.5  mm. 

"Location :     Channahon,    Will    County,    Illinois." 

This  species  closely  resembles  P.  determinatus  Foerste,  but  differs 
from  that  form  in  the  slightly  more  prominent  glabella  and  deeper 
glabellar  furrows.  It  is  very  common  in  the  limestone  near  Channahon, 
Illinois. 

Cyphaspis  intermedia  Weller 
( Plate  IX,  figure  26) 
1907.     Cyphaspis  intermedia.     Weller,    Bull.   Chicago   Acad,   of    Sci.,    No.   4,   pt.   2, 
p.  231,  pi.  20,  figures  3-5. 

Weller's  description  :  "Glabella  semi-elliptical  in  outline,  about  three- fourths 
the  length  of  the  head,  rounded  in  front  and  truncate  behind,  strongly  convex 
longitudinally  and  transversely,  surrounded  laterally  and  anteriorly  by  a  narrow 
but  well  defined  dorsal  furrow,  the  bottom  of  which  is  a  little  impressed  below 
the  inner  margin  of  the  cheeks ;  at  the  base  of  the  glabella  are  a  pair  of  small 
but  well-defined  lateral  lobes  which  extend  about  half  way  up  the  sides  of  the 
glabella,  they  are  separated  from  the  main  portion  of  the  glabella  by  the  posterior 
glabellar  furrows  which  originate  at  the  dorsal  furrows  about  two-thirds  the 
distance  from  the  anterior  extremity  of  the  glabella  to  the  occipital  furrow,  they 
describe  a  slight  curve  obliquely  backward  and  inward,  meeting  the  occipital 
furrow  about  half  way  between  its  middle  point  and  the  dorsal  furrows ;  a  sec- 
ond pair  of  lateral  furrows  are  slightly  impressed  in  the  sides  of  the  glabella  just 
above  the  dorsal  furrows,  just  in  front  of  the  mid-length  of  the  glabella.  The 
occipital  furrow  is  narrow  and  shallow.  The  occipital  segment  is  narrow  and 
flat,  its  surface  being  considerably  depressed  below  the  glabella.  The  fixed  cheeks 
extend  nearly  horizontally  from  the  dorsal  furrows  into  the  palpebral  lobes  which 
lie  opposite  the  outer  extremities  of  the  posterior  glabellar  furrows;  in  front 
and  back  of  the  palpebral  lobes  the  surface  slopes  away  rather  abruptly  from 
the  dorsal  'furrows  and  is  continuous  around  the  anterior  extremity  of  the  gla- 
bella as  a  rather  broad,  slightly  convex,  sloping  area  between  the  dorsal  furrow 
and  the  marginal  border.  Marginal  border  sharply  defined  and  rather  broad. 
Free  cheeks  not  preserved  in  any  of  the  species  observed.  Thorax  and  pygidium 
unknown.  Entire  surface  of  the  cranidium  covered  with  fine  papillae  which  are 
more  crowded  upon  the  cheeks,  being  nearly  obsolete  upon  the  marginal  border, 

"The  dimensions  of  the  best  preserved  specimen,  a  cranidium,  are :  length 
5  mm. ;  width  between  the  margins  of  the  palpebral  lobes,  approximately  5.7  mm. ; 
length  of  glabella  and  occipital  segment  4.25  mm.;  convexity  of  glabella  1.2  mm. 

"Locality :     Channahon,  Will  County,  Illinois. 


ALEXANDRIAN  SERIES  159 

Glabellae  of  this  species  are  common  in  the  limestone  near  Chan- 
nahon,  in  Will  County,  Illinois.  This  form  differs  from  C.  clintonensis 
Foerste,  mainly  in  the  proportionately  shorter  glabella. 

Metapolichas  ferrisi  Weller 
(Plate  IX,  figures  23  and  24) 
1907.     Metapolichas   ferrisi.     Weller,    Bull.    Chicago    Acad.'  of    Sci.,    No.   4,    pt.    2, 
p.  224,  pi.  22,  figures  12,  13. 

Weller's  description  :  "Entire  body  sub-elliptical  in  outline.  Cranidium  sub- 
triangular  in  outline,  broadly  rounded  or  sub-truncate  in  front.  Glabella  depressed- 
convex,  about  as  wide  as  long,  bordered  laterally  by  shallow  but  well-defined  dorsal 
furrows,  narrowest  a  little  back  of  a  line  joining  the  eyes,  a  little  broader  at 
the  occipital  segment  than  in  front;  median  lobe  occupying  the  entire  width  of 
the  glabella  in  front,  rapidly  becoming  narrower  posteriorly  until  in  line  with 
the  eyes  it  occupies  only  one-third  the  width  of  the  glabella,  posteriorly  it  is 
nearly  confluent  with  the  third  lateral  lobes  externally ;  first  lateral  furrows 
strong  and  well  defined,  curving  from  just  back  of  the  antero-lateral  extremities 
of  the  median  lobe,  backward  and  inward,  nearly  parallel  with  the  dorsal  furrows 
to  a  point  just  back  of  the  line  joining  the  eyes,  where  they  are  continuous  with 
the  third  lateral  furrows,  making  a  sharp  turn  outward  and  forward  around  the 
posterior  extremities  of  the  anterior  lateral  lobes,  this  inner  well-defined  portion 
of  the  third  lateral  furrows  is  short,  being  continued  obliquely  forward  to  the 
dorsal  furrows  as  slight  depressions  which  are  sometimes  almost  obsolete ;  second 
lateral  furrows  represented  by  slight  indentations  of  the  anterior  furrows  into 
the  inner  sides  of  the  anterior  lateral  lobes  at  about  the  middle  of  their  length  ; 
anterior  lateral  lobes  compound,  sub-elliptical  in  outline,  the  longer  axis  a  little 
more  than  twice  the  shorter,  directed  outward  and  forward,  confluent  posteriorly 
towards  the  dorsal  furrow  with  the  third  lateral  lobes;  third  lateral  lobes  much 
smaller  than  the  anterior  ones,  ill-defined,  separated  from  the  median  lobe  by 
slight  depressions  only,  which  may  sometimes  be  almost  obsolete,  from  the  anterior 
lateral  lobes  they  are  sharply  separated  within  but  laterally  towards  the  dorsal 
furrows  they  are  almost  wholly  confluent.  Occipital  furrow  shallow,  rather  broad 
and  ill-defined  in  the  center,  becoming  more  strongly  defined  laterally  where  it 
divides,  the  two  divisions  on  each  side  surrounding  a  small,  sub-ovate  or  slightly 
sub-rhombic  occipital  lobe.  Occipital  segment  rather  broad  and  flattened  in  the 
middle,  a  little  narrower  and  more  convex  laterally.  Fixed  cheeks  very  narrow 
in  front  of  the  eyes,  connected  anteriorly  around  the  front  of  the  glabella  by  a 
narrow,  flat,  marginal  border,  back  of  the  eyes  they  are  much  broader  and  are 
produced  laterally,  they  are  crossed  near  the  posterior  margin  by  the  well-de- 
fined posterior  cheek  furrows,  between  the  eyes  and  the  posterior  cheek  fur- 
rows the  surface  is  gently  convex  and  slopes  laterally  and  posteriorly.  Palpebral 
lobes  small,   free  cheeks  unknown. 

"The  thorax  is  represented  in  the  specimens  studied  only  by  detached  and 
broken   segments.     The   axis   is   apparently  broad    and   depressed-convex. 

"Pygidium  depressed-convex,  semi-elliptical  in  outline ;  the  axis  depressed, 
but  little  elevated  above  the  surface  of  the  pleura,  occupying  more  than  one-third 
of  the  entire  width  of  the  pygidium  anteriorly,  crossed  anteriorly  by  two  transverse 
furrows,  the  first  of  which  is  much  better  defined  and  continuous  across  the 
entire  width  of  the  axis,  the  second  one  is  less  sharply  defined,  and  is  not  con- 


160  BIENNIAL   REPORT 

tinuous  across  the  median  portion  of  the  axis,  each  of  the  two  lateral  portions 
curving  backward  toward  their  inner  extremities ;  posteriorly  the  axis  is  produced 
into  a  depressed  post-axial  region,  the  dorsal  furrows  converge  posteriorly  to 
about  the  middle  of  the  pygidium  where  the  axial  region  is  about  one-half  its 
width  at  the  anterior  margin,  from  here  the  dorsal  furrows  diverge  posteriorly, 
the  axial  region  again  becoming  broader,  the  furrows  do  not  reach  the  posterior 
margin  of  the  pygidium  so  that  the  axial  region  is  coalescent  posteriorly  with  the 
pleural  segments  on  either  side.  The  pleura  are  divided  into  three  pairs  of 
broad  grooved  segments,  the  posterior-lateral  angles  of  the  two  anterior  pairs 
project  slightly  beyond  the  border  of  the  pygidium  as  posteriorly  projecting  free 
points,  between  the  free  points  of  the  second  pleural  segments  the  border  is 
continuous. 

"The  entire  surface  of  the  head,  pygidium  and  thoracic  segments  is  covered 
with  small,   more  or  less  irregular,   rounded  papillae. 

"The  dimensions  of  the  best  preserved  cranidium  observed  are :  length  17.5 
mm. ;  approximate  width  between  the  eyes  18.5  mm. ;  width  at  posterior  margin 
30  mm. ;  width  of  median  lobe  of  glabella  in  front  13  mm.  The  best  preserved 
pygidium  has  the  following  dimensions :  length  16  mm. ;  width  24  mm. ;  width 
of  axis  at  anterior -margin  9  mm.;  width  of  axial  region  at  narrowest  point  4  mm. 

"Locality :     Near  Channahon,  Will  County,   Illinois." 

This  species  is  very  closely  allied  to  M.  breviceps  var.  clintonensis 
in  the  lobation  of  the  glabella,  which  shows  a  small,  oblong  lobe  in  the 
occipital  furrow  beneath  each  of  the  lateral  lobes,  and  in  the  presence 
of  a  third  pair  of  lateral  glabellar  lobes.  It  is  very  abundant  in  the 
limestone  near  Channahon,  in  Will  County,  Illinois. 

Ostracoda 

Lepcrditia  illinoisensis  n.sp. 
(Plate  IX,  figure  27) 

Shell  differing  from  Lepcrditia  faba  Hall,  of  the  Niagaran,  in  being 
shorter  and  more  nearly  circular  in  outline,  and  in  having  the  greatest 
convexity  near  the  middle.  The  valves  are  subequally  convex,  and  over- 
lapping; hinge  line  central,  1  mm.  long;  about  one-half  the  greatest 
length  of  the  shell.  Width  of  the  valve,  1.25  mm.;  length  about  2  mm. 
The  anterior  and  posterior  ends  subequally  convex  and  the  base  reg- 
where  it  is  associated  with  Dalmanella  cf.  edgewoodensis,  Proetus  chan- 
nalwncnsis,  and  Cyphaspis  intermedia. 
ularly  rounded,  surface  smooth. 

This  species  occurs  in  the  upper  layers  of  the  Channahon  limestone, 
where  it  is  associated  with  Dalmanella  cf.  edgewoodensis,  Proetus  chan- 
nahonensis,  and  Cyphaspis  intermedia. 


PLATES 


Fig. 

1. 

Fig. 

2. 

Fig. 

3. 

Fig. 

4. 

Fig. 

5. 

Fig. 

6. 

Figs. 

7 

Fig. 

9. 

PLATE  III 

Fossils  from  the  Girardeau  Limestone 

Ptychcrifius  splendens  (S.  A.  Miller),  page  95 
View  of  the  type  specimen,  X  2  (after  Wachsmuth  and  Springer). 

Cyclocystoides  illinoiscnsis  Miller  and  Gurley,  page  96. 
Outer  rim  of  specimen,  and  a  fragment  of  the  outer  rim  of  another  speci- 
men,   (after   M.  and   G.) 

Nematopora  fragilis  Ulrich,  page  99. 
A  fragment  showing  mode  of  branching,  X  6. 

Nematopora  dclicatula   Ulrich,  page  98. 
A  portion  of  a  branch,   X  6. 

Nematopora  rctrorsa  Ulrich,  page  99. 
A  fragment  of  a  branch,  X  6. 

Nematopora  alternata  Ulrich,  page  98. 
A  portion  of  a  branch,  X  6. 

Lingulops  oiata  n.  sp.,  page   100. 
7  and  8.     View  of  a  complete  ventral  valve,  X  4. 

Rafinesquina?  dclicatula  n.  sp.,  page   100. 
View  of  the  type  specimen,  ventral  valve,   X  2. 

Rafinesquina  f  mcsicosta   (Shumard),  page  101. 
Fig.  10.     View  of  an  entire  ventral  valve,  X   l1/^. 

Lcptccna  rhomboidalis    (Wilckens),  page   101. 
Fig.  11.     View  of  an  incomplete  ventral  valve,   X    l/2. 

Schuchcrtella  missouricnsis  (Shumard),  page  102. 
Fig.  12.     Ventral  view  of  a  nearly  complete  shell. 
Fig.  13.     Dorsal  view  of  another  specimen,  both   X    \y2. 

Dalmanclla  modcsta  n.  sp.,  page   102. 
Fig.  14.     View  of  dorsal  valve,   X  2. 
Fig.  15.     View  of  type  specimen,  ventral  valve,   X  2. 

Homocspira  immatura  n.  sp.,  page  105. 
Fig.  16.     View  of  ventral  valve,    X    \]/2. 

Fig.  17.     View  of  another    (imperfect)    ventral  valve,   X    \y2. 
Fig.  18.     View  of  typical  specimen,  dorsal  valve,   X  2. 

Protozcuga  siilcocarinata  n.  sp.,  page  105. 
Fig.  19.     View   of  type  specimen,   dorsal  valve. 
Fig.  20.     Lateral  view  of  the  same  shell. 
Fig.  21.     The  same,  ventral  valve,  all  X  6. 

Rhynchotrcma?  illinoiscnsis  n.  sp.,  page  103. 
Ventral  view  of  the  type  specimen. 
Dorsal  view  of  same,   X   \]/2. 

Camarotccchiaf  festinata  n.  sp.,  page  104. 
Dorsal  view  of  the  type  specimen. 
Anterior  view  of  the  same  shell,  all  X  l/2. 
Fig.  26.     Ventral  view  of  the  same  specimen. 


Fig. 

22. 

Fig. 

23. 

Fig. 

24. 

Fig. 

25. 

ILLINOIS    STATE    GEOLOGICAL    SURVEY  BULLETIN    NO.    23,    PLATE    III 


PLATE  IV. 

Fossils  from  the  Girardeau  Limestone 

Pterinea  formosa  n.  sp.,  page   106 
Fig.     1.     View  of  left  valve  of  type  specimen,  X  2. 

Modiolopsis  concinna  n.  sp.,  page  107. 
Fig.     2.     View  of  left  valve  of  type  specimen,   X   2. 

DiapJwrostoma  niagarensis  var.  immatura  n.  var.,  page  108. 
Dorso-lateral  view  of  type  specimen. 

cf.  Cyclonema  canccllata  Hall,  page  108. 
Lateral  view  of  a  nearly  complete  specimen. 
Conradella  sp.,  page  107. 
Dorsal  view  of  an  imperfect  specimen,   X  3^4. 

Comulites  tenuistriatus  (Meek  and  Worthen),  page  97. 
Lateral  view  of  the  type  specimen. 

Comulites  incurvus  (Shumard),  page  97. 
Lateral  view  of  a  small  specimen,  with  a  portion  enlarged,  X  5  (after  Shu- 
mard). 

Calymene  dubia  n.  sp.,  page  112. 
Dorsal  view  of  an  entire  pygidium. 

Dorsal  view  of  an   incomplete   cranidium  of   the   typical   specimen. 
Encrintirus  dcltoideus  Shumard,  page  111. 
Fig.  10.     Dorsal  view  of  a  pygidium,  X  2. 

Acidaspis  halli  Shumard,  page  110. 
Fig.  11.     Dorsal  view  of  a  cranidium,  slightly  enlarged. 
Fig.  12.     Ventral  view  of  an  almost  entire  individual,  X  2. 

Cyphaspis  girardeauensis  Shumard,  page  109. 
Fig.     13.     Dorsal  view  of  a  cranidium,  X  4  (after  Shumard). 

Proetus  princeps  n.  sp.,  page  108. 
Fig.  14.     Dorsal  view  of  the  almost  entire  cranidium,  of  type  specimen,   X  3. 


Fig. 

3. 

Fig. 

4. 

Fig. 

5. 

Fig. 

6. 

Fig. 

7. 

Fig. 

8. 

Fig. 

9. 

Fossils  from  the  Edgewood  Limestone 

Calvinia  edgewoodcnsis  n.  gen.  n.  sp.,  page  116. 
Fig.  15.     View  of  the  upper  surface  of  the  corallum  of  type  specimen,  natural  size. 
Fig.  16.     Longitudinal  section  of  a  portion  of  another  corallum,  X  2. 
Fig.  17.     Transverse  section  of  a  portion  of  the  same  corallum,   X  4. 


ILLINOIS    STATE    GEOLOGICAL    SURVEY 


BULLETIN    NO.    23,    PLATE    IV 


/ 


t 


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10 


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11 


14 


'«*;,-    J*- 


&£  to 


15 


PLATE  V 


Fossils  from  the  Edgewood  Limestone 

Calapoocia  favositoidea  n.  sp.,  page  115. 
Lateral  view  of  the  corallum  of  type  specimen,  natural  size. 
Longitudinal  section  of  a  few  of  the  corallites  of  same,  X  2>l/2. 
Transverse  section  of  a  few  corallites  of  same,  X  3. 

Zaphrentis  cf.  stoke  si  Milne-Edwards  and  Haime,  page  113. 
Lateral  view  of  a  corallum. 

Zaphrentis  subregularis  n.  sp.,  page  113. 
Lateral  view  of  the  type  specimen. 

Lyellia  thebesensis  Foerste,  page  116. 
Longitudinal  section  of  a  portion  of  a  corallum,    X  4. 
View  of  the  surface  of  a  corallum  of  usual  size. 

Clathrodictyon  vesiculosum  Nicholson  and  Murie,  page  117. 
Fig.    8.     Vertical  section,  X  9. 

Favositcs  subelongus  n.  sp.,  page  114. 
Fig.     9.     View  of  the  upper  surface  of  a  corallum,  natural  size. 
Fig.  10.     Longitudinal  section  of  the  corallum  of  the  type  specimen,  natural  size. 


Fig. 

1. 

Fig. 

2. 

Fig. 

3. 

Fig. 

4. 

Fig. 

5. 

Fig. 

6. 

Fig. 

7. 

ILLINOIS    STATE    GEOLOGICAL    SURVEY 


BULLETIN    NO.    23,    PLATE    V 


V 
4 


.>._,.^^' 


Fig. 

1. 

Fig. 

2, 

Fig. 

3. 

Fig. 

4. 

Fig. 

5. 

Fig. 

6. 

Fig. 

7. 

PLATE  VI 


Fossils  from  the  Edgewood  Limestone 

Schuchertella  propinqua  (Meek  and  Worthen),  page  120. 
Ventral  view  of  an  exfoliated  shell. 

Schuchtertella  missouriensis  var.  convcxa  n.  var.,  page  121. 
View  of  the  ventral  valve  of  the  type  specimen,   X   l/2. 

LcptcB  rhomboidalis   (Wilckens),  page   101. 
Ventral  view   of   an   incomplete   shell. 

Brachyprion  stropheodontoides  n.  sp.,  page  119. 
View  of  the  ventral  valve  of  the  type  specimen,  and  a  profile  view  showing 
the  convexity  of  the  same,  X  1^. 

Brachypvion  latisculptilis  n.  sp.,  page  118. 
View  of  the  ventral  valve  of  the  typical  specimen,  X  2. 

Rafinesquina?  mcsicosta  var.  mcsistria  n.  var.,  page  118. 
View  of  the  ventral  valve  of  type,  X  1^. 

Orthis  flabcllites  var.   fissiplicata   Foerste,   page    122. 
Ventral  view  of  an  entire  valve,   X    1^. 

Platystrophia  daytoiiensis  Foerste,  page  122. 
Fig.     8.     Dorsal  view  of  a  complete  shell. 

Rhipidomella  tenuilineata  n.  sp.,  page  123. 
Fig.  9.  View  of  the  dorsal  valve  of  the  type  specimen,  X  2. 
Fig.  10.     Ventral  view  of  another  shell,  X  2. 

Dahnanella  cdgewoodensis  n.  sp.,  page  123. 
Fig.  11.     Lateral  view  of  the  type  specimen. 
Fig.  12.     View  of  dorsal  valve  of  same  shell. 
Fig.  13.     Ventral  view  of  the  same  shell. 

Atrypa  prccmarginalis  n.  sp.,  page  129. 
Fig.  14.     View  of  dorsal  valve  of  the  type  specimen,  X  \1/t,. 
Fig.  15.     Ventral  view  of  same,  X   \y$. 
Fig.  16.     View  of  ventral  valve  of  another  shell,  X  V/3. 

Hindella?  ambigua  n.  sp.,  page  133. 
Fig.  17.     Lateral  view  of  the  type  shell. 
Fig.  18.     Dorsal  view  of  the  same. 

Rhyuchotreta  thebesensis  Foerste,  page  126. 
Fig.  19.     Ventral  view  of  a  specimen  of  average  size. 
Fig.  20.     Dorsal  view  of  the  same  shell. 

Rhynchotrcta  thebesensis  var.  multistriata  n.  var.,  page   127. 
Fig.  21.     Ventral  view  of  the  type  specimen. 
Fig.  22.     View  of  the  dorsal  valve  of  the  same  shell. 

Homocospira  jiscello  striata  n.  sp.,  page  132. 
Fig.  23.     View  of  the  ventral  valve  of  the  type  specimen,   X   2. 
Fig.  24.     View  of  the  dorsal  valve  of  the  same  shell,  X  2. 

Atrypa  putilla  (Hall  and  Clarke),  page  130. 
Fig.  25.     Dorsal  view  of  an  entire  shell,   X  2. 

Homocospira  subcircularis  n.  sp.,  page  132. 
Fig.  26.     Dorsal  view  of  the  type  specimen,  X  2. 
Fig.  27.     View  of  the  ventral  valve  of  the  same  shell,  X  2. 


ILLINOIS    STATE    GEOLOGICAL    SURVEY 


BULLETIN    NO.    23,    PLATE   VI 


PLATE  VII 


Fossils  from  the  Edgewood  Limestone 

Camarotocchia?  antiqua  n.  sp.,  page  128. 
Fig.     1.     Ventral  view  of  the  type  specimen. 
Fig.     2.     Dorsal  view  of  the  same  shell. 

cf.  Rhynchonellaf  janea  Billings,  page  128. 
Fig.     3.     Dorsal  view  of  an  almost  complete  shell. 

Camarotocchia?  concinna  n.  sp.,  page  127. 
Fig.     4.     Dorsal  view  of  the  type  specimen,  X  2. 
Fig.     5.     Ventral  view  of  the  same  shell,   X  2. 

Protozeuga  sulcocarinata  n.  sp.,  page  105. 
Fig.     6.     Dorsal  view  of  complete  shell,  X  9. 

Clorindaf  thebesensis  n.  sp.,  page  125. 
View  of  the  ventral  valve  of  the  type  specimen. 
View  of  the  dorsal  valve  of  another  individual. 

Rhynchotreta  parva  n.  sp.,  page  125. 
Ventral  view  of  the  type  specimen,  X  l/2. 
Dorsal  view  of  the  same  shell,   X   l/2. 

Whitficldclla?  billingsana    (Meek  and  Worthen),  page  134. 
Dorsal  view  of  the  type  specimen. 
Ventral  view  of  another  specimen. 

Whitfieldella  ovoides  n.  sp.,  page  134. 
Ventral  view  of  the  type  specimen. 
Dorsal  view  of  another  typical  shell. 
Lateral  view  of  the  same  shell. 

Whitficldclla  speciosa  n.  sp.,  page  135. 
View  of  dorsal  valve  of  the  typical  specimen. 
View  of  ventral  valve  of  the  type,  both  X   \l/2. 

Pcntamcrus  parvulus  n.  sp.,  page  124. 
View  of  the  ventral  valve  of  the  type  specimen,  X  2. 
View  of  the  interior  of  the  same,  showing  the  spondylium,  X  2. 
View  of  the  dorsal  valve  of  another  shell,  X  2. 

View  of  the  interior  of  same  showing  the  septum  and  spondylium,   X 
Spirifcr  (Dclthyris)  sp.,  page  131. 
Fig.  22.     View  of  an  incomplete  ventral  valve,  X  2. 

Atrypa  tubulistriata  n.  sp.,  page  131. 
Fig.  23.     View  of  ventral  valve  of  the  type  specimen. 
Fig.  24.     View  of  the  dorsal  valve  of  the  type,  both  X  1*4. 

Ctcnodonta  subelliptica  n.  sp.,  page  136. 
Fig.  25.     View  of  the  left  valve  of  the  type  specimen,  X  l/2. 

Cypricardinia  siibquadrata  n.  sp.,  page  138. 
Fig.  26.     View  of  the  right  valve  of  the  type. 

Colpomya  abrupta  n.  sp.,  page  137. 
Fig.  27.     View  of  the  left  valve  of  the  type  specimen,  X   H. 

Ptcrinea  thebesensis  M.  and  W.,  page  136. 
Fig.  28.     View  of  the  left  valve  of  the  type  specimen. 

Straparollus  pumilis  11.  sp.,  page  142. 
Fig.  29.     Lateral  view  of  the  type  specimen,   X   5. 

Holopca  111  inn ta  n.  sp.,  page  143. 
Fig.  30.     Lateral  view  showing  aperture,  type  specimen,   X   6. 

Lophospira  thebesensis  n.  sp.,  page  140. 
Fig.  31.     Lateral  view  of  the  type  specimen. 


Fig. 

7. 

Fig. 

8. 

Fig. 

9. 

Fig. 

10. 

Fig. 

11. 

Fig. 

12. 

Fig. 

13. 

Fig. 

14. 

Fig. 

15. 

Fig. 

16. 

Fig. 

17. 

Fig. 

18. 

Fig. 

19. 

Fig. 

20. 

Fig. 

21. 

ILLINOIS    STATE    GEOLOGICAL    SURVEY  BULLETIN    NO.    2$,    PLATE    VII 


Odd 


10 


0 


a  0  4>  4> 


11 


12 


16 


13 


0 


0*0 

14  iy 

18 


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22 


15 


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21 


23 


20 


24 


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27 


25 


26 


28 


29 


a 


30 


31 


PLATE  VIII 


Pii 


Fig. 

2. 

Fig. 

3. 

Fig. 

4. 

Fig. 

5. 

Fig. 

6. 

Fig. 

7. 

Fig. 

8. 

Fig- 
Fig 
Fig 

Fig 

Fig- 
Fig 

Fig- 
Fig 
Fig 


Fossils  from  the  Edgewood  Limestone 

Diaphorostoma  niagarensis  (Hall),  page  144. 
Lateral  view  of  a  somewhat  imperfect  cast,  X  2. 

Bellerophon  consimilis  n.  sp.,  page  140. 
Dorsal  view  of  the  cast  of  the  type  specimen. 

Poleumita  bellasculptilis  n.  sp.,  page  143. 
Lateral  view  of  the  type  specimen,  X  2. 

Cycloncma  daytonensis  Foerste,  page  142. 
View  of  a  shell  of  normal  size. 

Liospira  cf.  affinc  (Foerste),  page  138. 
Lateral  view  of  a  specimen  of  about  the  average  size,   X   1J. 

Bellerophon  cf.  exiguus  Foerste,  page  141. 
Dorsad  view  of  a  cast  of  shell. 

Lophospira  faseiato  n.  sp.,  page  139. 
Lateral  view  of  the  type  specimen. 
Lateral  view  of  the  upper  portion  of  the  spire. 

Hormotoma  tenera  n.  sp.,  page  139. 
9.     View  of  the  type  specimen,  X  2. 

Proctus  determinatus  Foerste,  page  145. 

10.  Dorsal  view  of  an  incomplete  cranidium,  X  2>4. 

11.  Dorsal  view  of  an  almost  entire  pygidium,   X   \2/^. 

Cyphaspis  intermedia  Weller,  page  158. 

12.  Dorsal  view  of  an  almost  complete  cranidium,   X  iy2. 

Metapolichas  breviceps  var.  elintonensis  (Foerste),  page  146. 

13.  Dorsal  view  of  an  imperfect  cranidium,  X  2l/2. 

14.  Dorsal  view  of  an  almost  perfect  pygidium. 

Isotelus  longcevus  n.  sp.  page  144. 

15.  Dorsal  view  of  cranidium  of  the  type  specimen,  X  2. 

Dalmanites  danai  Meek  and  Worthen,  page  147. 

16.  Dorsal  view  of  a  cephalon  of  a  little  above  the  average  size. 

17.  Dorsal  view  of  a  complete  pygidium  of  another  individual. 


ILLINOIS    STATE    GEOLOGICAL    SURVEY 


BULLETIN    NO.    23,    PLATE   VIII 


«■•    » 


Fig. 

1. 

Fig. 

2. 

Fig. 

3. 

Fig. 

4. 

Fig. 

5. 

Fig. 

6. 

Fig. 

7. 

Fig. 

8. 

Fig. 

9. 

Fig. 

10. 

Fig. 

11. 

Fig. 

12. 

PLATE  IX 

Fossils  from  the  Channahon  Limestone 

Zaphrentis  subregularis  n.  sp.,  page  113. 
Lateral  view  of  a  specimen  of  moderate  size. 

Zaphrentis  ambigua  n.  sp.,  page  149. 
View  of  the  type  specimen. 

Lingulops  iUinoisensis  n.  sp.,  page   150. 
View  of  the  cast  of  the  interior  of  ventral  valve,  X  7. 
View  of  the  interior  of  the  ventral  valve  of  the  type  specimen,  X  7. 

Pholidops  subelliptica  n.  sp.,  page  150. 
View  of  surface  of  ventral  valve  of  type  specimen,  X  A]/2. 

Schuchertella  curvistriata  n.  sp.,  page  151. 
View  of  the  dorsal  valve  of  the  type  specimen. 

Atrypa?  sp.,  page  154. 
View  of  the  ventral  valve  of  a  specimen  of  average  size,   X  4^4. 
View  of  a  dorsal  valve  of  another  individual,  X  3^2. 
Dalmanella  edyewoodcnsis  n.  sp.,  page  123. 
View  of  a  complete  ventral  valve,  X  l/2. 

Rhipidomella  hybrid  a  (Sowerby),  page  152. 
View  of  the  ventral  valve  of  an  average  specimen. 

IVhitficIdclla  acuminata  n.  sp.,  page  154. 
View  of  the  dorsal  valve  of  the  type  specimen. 
Ventral  view  of  the  same  shell. 

IVhitficIdclla  oroides  n.  sp.,  page  134. 
Fig.  13.     View  of  a  nearly  complete  ventral  valve. 

Rhynchotreta  intermedia  n.  sp.,  page   153. 
Ventral  view  of  the  type  specimen. 
Dorsal  view  of  the  same  shell. 

Rhynchotreta  lepida  n.  sp.,  page  152. 
View  of  the  ventral  valve  of  the  type  specimen,   X  2. 
Dorsal  view  of  the  same  shell,  X  2. 

Ptcrinca  elegans  n.  sp.,  page  154. 
View  of  the  left  valve  of  the  type  specimen,  X  1^. 

Diaphorostoma  iUinoisensis  n.  sp.,  page  156. 
Lateral  view  of  the  type  specimen,  X  \l/2. 

Calloncma  pristina  n.  sp..  page  155. 
Lateral  view  of  the  type  specimen,   X   1T4- 

Cycloncma  daytonensis  Foerste,  page  142. 
View  of  a  nearly-  complete  individual  of  moderate  size. 
Dawsonoccras  tcnuilincatum  n.  sp.,  page   156. 
Longitudinal  view  of  a  portion  of  the  type,  at  about  one-half  the  greatest 
diameter. 

MetapolichaS  fcrrisi  Weller,  page  159. 
Dorsal  view  of  a  nearly  complete  cranidium,  X  l2/^. 
Dorsal  view  of  an  entire  pygidinm. 

Proetus  channahonensis  Weller,  page  157. 
Dorsal  view  of  a  nearly  complete  cranidium,  X  \2/$. 

Cyphaspis  intermedia  Weller,  page   158. 
Dorsal  view  of  an  almost  entire  cranidium,   X   2. 

Lcperditia    iUinoisensis  n.  sp.,   page    160. 
View  of  the  left  valve  of  the  type  specimen. 


Fig. 

14. 

Fig. 

15. 

Fig. 

16. 

Fig. 

17. 

Fig. 

18. 

Fig. 

19. 

Fig. 

20. 

Fig. 

21. 

Fig. 

22. 

Fig. 

23. 

Fig. 

24. 

Fig. 

25. 

Fig. 

26. 

Fig. 

27. 

ILLINOIS    STATE    GEOLOGICAL    SURVEY  BULLETIN    NO.    2$,    PLATE    IX 


INDEX 


Page 
Acidaspis   halli   Shumard 110 

Alexander  County,  Alexandrian 

series  in   69,  72 

Sexton  Creek  limestone  in 87 

silica  from   42 

Alexandrian    series,    Channahon 

limestone   of 84-86,  149-160 

definition   of    68 

distribution   of    69 

Edgewood  limestone  of.  .75-86,  113-160 

Essex   limestone   of 86-87 

Girardeau  limestone  of. .  .73-75,  95-112 
Sexton  Creek  limestone  of ..  .68,  87-91 
stratigraphy   of    72-94 

Analyses  of  : 

artesian   water    64 

coal  No.  2 62 

Illinois  coals    14 

Annulosa    in    Girardeau    limestone. 97-98 

Anthozoa  in  : 

Channahon   limestone    149-150 

Edgewood  formation  113-117 

Artesian  water,  occurrence  of 63-65 

Artesian    wells    in    La  Salle-Henne- 
pin  quadrangles    58,  64,  65 

Arthropoda  in  : 

Channahon    limestone    157-160 

Edgewood    formation    144-149 

Girardeau    limestone    108-112 

Atrypa?  sp.   154 

praemarginalis    n.sp    129 

putilla   (Hall  and  Clarke) 130 

tubulistriata   n.sp 131 


Bartow,    Edward,   work   of 12 

Bellerophon  consimilis  n.sp 140 

exiguus    Foerste    141 

Big   Muddy  Valley,  maps   of 16 

Birmingham,  drilling  near 49 

Black  Hollow,  clays  from 62 

Blatchley,  R.  S.,  work  of 12,15 

Bleininger,  A.  V.,  work  of 12 

Bowling  Green  limestone 77 

Brachiopoda   in  : 

Channahon    limestone    150-154 

Edgewood    formation    118-136 

Girardeau  limestone  100-106 

Brachyprion  latisculptilis  n.sp 118 

stropheodontoides  n.sp 119 

Brassfield   limestone,   see  Sexton   Creek 
limestone. 


Page 
Bryozoa  in  : 

Edgewood    formation    118 

Girardeau    limestone    98-99 

Bureau,   artesian   wells   at    65 

sand  and  gravel  from   61 

Bureau     County,    see    Hennepin    quad- 
rangle. 

C 

Cady,   G.   H,   work  of 12,16 

Calhoun  County,  Alexandrian  series 

in     . 69 

Essex  limestone  in   86 

Callonema  pristina  n.sp 155 

Calopoecia  favositoidea  n.sp 115 

Calrinia    nov.gen 115 

edgewoodensis  n.sp 116 

Calymene   dubia   n.sp 112 

Camarotoechia?  antiqua  n.sp 128 

concinna  n.sp 127 

festinata    n.sp 104 

Carbondale    formation    in    western 

Illinois    46 

Carlinville,  oil  and  gas  near   15,  33 

Carlyle   oil  field    15,33 

Cedar  Point,  artesian  wells  at 65 

Cement,  production  of  41 

Centralia-Sandoval  oil  field  33 

Cephalopoda    in    Channahon    lime- 
stone     156-157 

Channahon,     section     of     limestone 

near    84 

Channahon   limestone    84 

description  of  fossils  from 149-160 

Carbondale    formation    in    western 

Illinois     46 

Chester  formation,  studies  of 14,  48 

Clathrodictyon  vesiculosum  Nichol- 
son &  Murie   117 

Clay,     in     Hennepin    and     La  Salle 

quadrangles    62 

production  of    38 

studies   of    15,  16 

Clay  products,  production  of 38 

Clorinda?  thebesensis  n.sp 125 

Coelenterata  from  : 

Channahon   limestone    149-450 

Edgewood    formation    113-117 

Coal,   in   Hennepin-La   Salle  quad- 
rangles          62 

production  of    29 

production  by  counties   30-31 

production  in  Illinois  since  1853..      28 
studies   of    14-16 


INDEX— Continued 


Page 
"Coal   Measures,"    in   Hennepin-La 

Salle  quadrangles    60-61 

sandstone   from    39 

Coal    Mining   Investigations,    estab- 
lishment of    12 

Coal  No.  1  in  western  Illinois 47 

Coal  No.  2,  analyses  of,  from  Hen- 
nepin-La  Salle   quadrangles ...       62 
in    Colchester-Macomb    quad- 
rangles     46,  48 

Coke,  production  of   32 

Colchester,  formations  near 46,  47 

Colchester-Macomb    qu  a  d  r  a  n  g  1  e  s , 

geology  of    45-50 

Collins  well  No.  1,  log  of 52-53 

Cook  County,  clay  products  in 38 

Cooperation  with  : 

Department    of    Applied    Chemis- 
try  14,  15 

Department  of  Ceramic  Engineer- 
ing     ; 15 

Mining  Engineering  Department.      14 

U.   S.   Bureau  of   Mines    14 

U.  S.  Geological  Survey 14,  26,  55 

University  of  Illinois 14 

Cooperative  Coal  Mining  Investiga- 
tions, establishment  of   12 

Colpomya  abrupta  n.sp 137 

Conradella    sp 107 

Cormilitcs  incurvus  (Shumard)  ....      97 
tenuistriatus  (Meek  &  Worthen) .      97 
Crawford  County,  natural-gas  gaso- 
line  from    37 

oil  wells  drilled  in  34 

Crinoidea  in  Girardeau  limestone.  .95-96 

Ctenodonta  subeUiptica  n.sp 136 

Cumberland     County,     overflowed 

lands    in    17 

Custer    Park,    Sexton    Creek    lime- 
stone  near    89 

Cycloncma  cancellata  Hall  108 

daytoncnsis  Foerste  142,  156 

Cyclocvstoidcs   illiuoiscnsis    (Miller 

&   Gurley)    96 

Cyphaspis   intermedia    (Weller) .  146,  158 

girardeauensis  Shumard    109 

Cypricardinia  subquadrata  n.sp 138 

Cyrene  limestone  member 76,78-79 

D 

Dalmanella  edgewoodensis  n.sp 123 

cf.  edgewoodensis  n.sp 151 

modesta  n.sp 102 

Dahnanites  danai  Meek  &  Worthen  147 

Dawsonoceras  tenuilineatum  n.sp...  156 

Deep  borings,  studies  of  21 


Page 

Deep  drilling  near  Birmingham....  49 

Deer  Park,  artesian  wells  at 64 

clays  from   62 

Depue,  artesian  wells  at 65 

sand  and  gravel  from 61 

Devonian  formation,  artesian  water 

from     65 

limestone  from  40 

silica  from    42 

Diaphorostoma  illinoisensis  n.sp 156 

niagarensis   Hall    144 

niagarensis  var.  immattira  n.var. .    108 
Drainage  surveys  and  maps. ...  16,  18-20 

E 

Early  Wisconsin  drift 61 

Echinodermata   in    Girardeau    lime- 
stone     95-96 

Edgewood  limestone  : 

Bowling  Green  member  of 77 

Channahon  limestone  of 84 

Cyrene  member  of 76 

Noix  oolite  of 77 

occurrence  and  stratigraphy  of .  . .  75 

paleontology  of   113-160 

section  of,  at  or  near : 

Edgewood,    Missouri    81 

Gale 79 

Louisiana,  Missouri 81 

Thebes  78 

Educational  bulletins    16 

Embarrass  Valley,  reclamation  in..  16 

Encrinurus  deltoidcus  Shumard....  Ill 

Essex,  section  of  limestone  near.  ...  86 
Essex    limestone,    occurrence    and 

stratigraphy  of   86 

paleontology  of 87 

Expenditures  by  Survey 22-23 

F 

Farosites  snbelongus  n.sp 114 

Financial  statistics  of  Survey 22-23 

Fluorspar,  production   of 41 

Fossils,  comparative  tables  of..  82,  83,  85 
descriptions  of  species  from  : 

Channahon  limestone 149-160 

Girardeau  limestone    95-112 

Edgewood  formation 113-149 

in  Edgewood  limestone 78,  79 

in  Essex  limestone 87 

in   Girardeau  limestone 74 

in   Sexton  Creek  limestone 90-91 

Franklin  County,  coal  in 29 

Fulton  County,  overflowed  lands  in      17 

G 

Gale,   section   of   Edgewood   forma- 
tion near    79 


INDEX— Continued 


Page 
Gallatin    County,    overflowed    lands 

in 17 

Galena  dolomite,  lead  and  zinc  in.  .  .  43 

Galena  region,  bulletin  on 21 

Galena-Trenton     limestone,     water 

from     65 

in     H  e  n  n  e  p  i  n-L  a  S  a  1 1  e    quad- 

rangles 60 

Gas  in  surface  deposits 48 

Gas,  see  Oil  and  gas. 

Gasoline,    production    from    natural 

gas    37 

Gastropoda    in    Girardeau    lime- 

•       stone    107-108 

Geological  Survey,  organization  of.  11 

expenditures  of   22-23 

Girardeau  limestone,  occurrence  and 

stratigraphy  of   73 

paleontology  of   95-149 

Glacial     deposits     in     Hennepin-La 

Salle  quadrangles   59,  61 

Glass   sand    41,  63 

Grant,  U.  S.,  work  of 12 

Gravel,  see  Sand  and  gravel. 

Griggsby  well  Xo.  1,  log  of 53 

H 

Hancock  County   45 

Hamburg,    Sexton   Creek   limestone 

near    88 

Hardin  County,  fluorspar  from....  42 

lead  and  zinc  in 43 

overflowed  lands  in 17 

Hardinville    quadrangle,    investiga- 
tion of  15 

Hennepin,  artesian  wells  at 65 

Hennepin  quadrangle,  see  La  Salle- 
Hennepin   quadrangles. 

Hindella  ambigua  n.sp 133 

Hoing  well  No.  1,  description  of. .  .51,  52 

Holopea  niinuta  n.sp 143 

Homeospira  fiscellostriata   n.sp 132 

immature!  n.sp 105 

subcircularis  n.sp 132 

Honnotoma  tencra  n.sp 139 

Hydrozoa  in  Edgewood  formation.  117 

I 

Illinois,  mineral  products  of 26,  27 

Illinois  River  valley 59 

Illinois    State    Museum,    fossils 

loaned  by   95 

Isotelus  longaei'us  n.sp 144 


Page 
J 

Jasper  County,  overflowed  lands  in.  17 
Tersey    County,    Alexandrian    series 

in 69 

Essex  limestone  in 88 

Joliet,  production  of  coke  at 32 

K 

Kankakee    County,    Alexandrian 

series  in  69 

Essex  limestone  in 86 

Kaskaskia  Valley,  maps  of 16 

Kay,  F.  H.,  work  of 12 

Kirkwood  sand  33 


La  Salle,  artesian  wells  at 65 

glass  sand  at 41,  63 

sand  and  gravel  from 61 

La  Salle  anticline,  oil  in 33 

in  La  Salle-Hennepin  quadrangles       60 
La  Salle  County  : 

natural   cement   from 41 

Portland  cement  rock  in 63 

La  Salle-Hennepin  quadrangles, 

investigations   in    55-63 

Lawrence  County,  natural-gas  gaso- 
line  from    37 

petroleum  in    33 

Lead,  zinc,  and  silver  production  of      43 

Leperditia  illinoisensis  n.sp 160 

Lcptaena  rhomboidalis  (Wilckens)  . 

101,120 

Lime,  production  of 40 

Limestone,  from  upper  Illinois  Val- 
ley  41,61,63 

production  of    , 39 

Lindgren,  J.  M.,  work  of 12,  16 

Lingulops  illinoisensis  n.sp 150 

oi  ata  n.sp 100 

Liospira  cf.  affine    (Foerste) 138 

Logs    of    Collins,    Hoing,    Griggsby 

wells   52,53 

Lophospira  fasciata  n.sp 139 

thebesensis   n.sp 140 

Lowell,  clays  from 62 

Lower  Magnesian  limestone  in  : 

La  Salle   and    Hennepin   quad- 
rangles     61,  63 

La  Salle  County   41 

Lxcllia   thebesensis   Foerste 116 

M 

Macomb    quadrangle,    see    Colches- 
ter-Macomb   quadrangles. 


INDEX— Continue  d 


Page 
McClosky  sand  in  Lawrence  County      33 

McDonough  County   45 

McFarland,  D.  F.,  work  of 12 

McLeansboro  limestone  for  flux...      40 
Metapolichas  breviceps  var.  clinton- 

cnsis    (Foerste)    146 

ferrisi  Weller  159 

Mineral,  paint 44 

products   of    Illinois 27 

resources  in  Illinois  in   1911   and 

1912   26-44 

statistics    26 

water,   production  of 42 

Mining    Engineering    Department, 

cooperation  with    14 

Mississippian    brachiopods 21 

Mississippian   series,   near    Colches- 
ter    . . 47 

Keokuk  limestone  of 48 

limestone   quarries   in 40 

oil  in    33 

St.   Louis   limestone  of 47 

Modiolopsis  concinna  n.sp 107 

Mollusca  in  : 

Channahon    limestone    154-157 

Edgewood  formation 136-144 

Girardeau    limestone    106-108 

Molluscoidea  in  : 

Channahon  limestone 150-154 

Edgewood  formation  118-136 

Girardeau  limestone  98-106 

Murphysboro  coal  in  Western  Illi- 
nois    46,48 

N 

Natural  gas,  as  source  of  gasoline.      37 

production  and  uses  of 36,37,46 

Natural  cement  41,  63 

Ncmatopora  alternata  Ulrich 98 

delicatula  Ulrich    98 

fragilis  Ulrich 99 

retrorsa    Ulrich    99 

Niagaran  limestone   65 

Noix  oolite   77 

O 

Oil  and  gas,  conditions  for  accumu- 
lation of   49 

in  western  Illinois    45-50,  51 

Wabash  County   33 

Carlinville    33 

studies   of    14,  15 

wells  in  Illinois  by  counties,  1910- 

1912    35 

Ordovician     formations,     limestone 

from   40 

sandstone  from 39 

Oregon,  glass  sand  at 41 


Page 
Orthis     fiabcllitcs     var.     fissiplicata 

Foerste    122 

Ostracoda  in  Channahon  limestone.    160 

Ottawa,  glass  sand  at 41,  63 

Overflowed  lands,  studies  of 16,  17 

P 

Paleontology  of  Alexandrian  series 

67-160 

Parr,  S.  W.,  work  of 12 

Pelecypoda   in  : 

Channahon  limestone 154-156 

Edgewood  formation 136-144 

Girardeau  limestone 106-107 

Pennsylvanian  series  in  western  Illi- 

_  nois     46 

limestone   from,   for  fluxing 40 

Pentamerus  parvulus  n.sp 124 

Petroleum,    production    and    prices 

of   33,34 

Pholidops  subclliptica  n.sp 150 

Pig  iron,  production  of 32 

Platteville  limestone,  lead  and  zinc 

in    43 

Platystrophia  daytoncnsis  Foerste..  122 
Pleasant   Hill,    Sexton   Creek   lime- 
stone near    89 

Plymouth  oil  field 51-53 

Poleumita  bellasculptis  n.sp 143 

Pope  County,  fluorspar  from 42 

lead  and  zinc  from 43 

Portland,  artesian  wells  at. 65 

Portland  cement  rock 63 

Pottsville  formation  in  western  Illi- 
nois      46 

Princeton,  artesian  wells  at 65 

Proetus  channahonensis  Weller 157 

dcterminatus  Foerste    145 

princcps  n.sp 108 

Protozeuga   sulcocarinata   n.sp.     105,  129 

Pterinea  elegans  n.sp 154 

formosa   n.sp 106 

thebesensis  Meek  and  Worthen..  136 
Putnam    County,   see  La  Salle-Hennepin 

quadrangles. 

Pyrite,  production  of 43 

Ptychocrinus  splcndens  (S.  A.  Mil- 
'  ler)     95 

R 

Rafinesquina?  delicatula  n.sp 100 

?  mesicosta  (Shumard) 101,  118 

?  mesicosta  var.  mesistria  n.var. . .    118 

Reclamation  of  overflowed  lands..  16,  17 

Rhipidomella  hybrida    (Sowerby)..    152 

tenuilineata  n.sp 123 


INDEX— Concluded 


Page 

Rhynchonella  ?  janea  Billings 128 

Rhynchotrema   ?  illinoisensis  n.sp..  103 

Rhyncotreta   intermedia   n.sp 153 

lepida   n.sp 152 

parva  n.sp 125 

thebesensis  Foerste   126 

thebesensis  var.  multistriata  n.var.  127 

S 

St.  Louis  limestone  in  western  Illi- 
nois      47 

St.  Peter  sandstone,  artesian  water 

from     65 

glass  sand  from 41 

in  La  Salle-Hennepin  quadrangles  60 
Saline  County,  overflowed  lands  in.  16,  17 

Salisbury,  R.  D.,  work  of 12,  16 

Sauer,  C.  O.,  work  of 12,  16 

Savage,  T.  E.,  work  of 12 

Sand  and  gravel,  in   La  Salle-Hen- 
nepin quadrangles   61 

production  of    41 

Sandstone,  production  of 39 

Schuchertella  curvistriata  n.sp 151 

cf.   missouricnsis    (Shumard)....  121 

missouriensis  (Shumard)    102 

missouriensis  var.  convexa  n.var.  121 

propinqua  (Meek  and  Worthen) .  120 

Schuyler  County    45 

Sexton    Creek   limestone,    fossils 

from    90,91 

occurrence  and  stratigraphy  of..  87,  89 

Shaw,  E.  W.,  work  of 21 

Shockel,  B.  H.,  work  of 21 

Silica,  production  and  uses  of 42 

Silurian   formation,  limestone  from  40 
Silver,  see  Lead,  zinc,  and  silver. 
South  Chicago,  production  of'  coke 

at  32 

Spirifcr  (Dethyris)  sp 131 

Spoon  River,  maps  of 16 

Spring    Valley,    sand    and    gravel 

from     61 

Starved  Rock  State  Park 65 

Stone,  production  of 39-40 

Straparollus  pumilis  n.sp 142 

Stratigraphic    studies    in    various 

quadrangles    14 

Stratigraphy     of     Alexandrian     se- 
ries   67-160 

Stromatoporidea  in  Edgewood  for- 
mation      117 

Stull,  R.  T,  work  of 12 

Sulphuric  acid 43 

Sumner   quadrangle,   investigation 

of    15 


Page 
T 

Thebes,  sections  near 73,  78 

Topographic  surveys    17 

Tracey  sand  in  Lawrence  County.  .      33 
Trilobita    in     Channahon    lime- 
stone     157-160 

in  Edgewood  formation 144-149 

in  Girardeau  limestone 108-112 

Tripoli,   see  Silica. 

Triumph,  sand  and  gravel  at 65 

Trowbridge,  A.  C,  work  of 21 

U 

Udden,  J.  A.,  work  of 12 

Union    County,    Alexandrian    series 

in  69 

silica  from  42 

U.    S.    Bureau    of    Mines,    coopera- 
tion  with    14 

work  of   12,37 

U.    S.   Geological   Survev,   coopera- 
tion with   14,  26,  55 

University    of    Chicago,    fossils 

loaned  by   95 

University    of    Illinois,    cooperation 

with  14,15 

Utica,  artesian  wells  at 64 

clays  from   62 

natural-cement  plant  at 41 

V 

Vermes  in  Girardeau  limestone. ..  .97-98 
Vermilion  County,  pyrite  in 43 

W 

Wabash  County,  oil  in 33 

Waters,  mineral,  production  of....  42 

Waukegan,  production  of  coke  at..  32 

Weller,  Stuart,  work  of 12 

Wells,  studies  of 14,  64,  65 

oil,  see  Oil  and  gas  and  Log. 

West  Virginia,  coking  coal  from...  32 

White,  K.  D.,  work  of 12 

Whitfieldella   acuminata  n.sp 154 

billingsana   (Meek  and  Worthen)  134 

ovoidcs  n.sp 134,  154 

?  speciosa  n.sp 135 

Williamson  County,  coal  in 29 

overflowed  lands   in 17 

Will  County,  Alexandrian  series  in.  69 

Z 

Zaphrentis  ambigua  n.sp 114,  149 

cf.    stokesi     Milne-Edwards    and 

Haime 113 

subrcgularis  n.  sp 113,  150 

Zinc,  see  Lead,  zinc,  and  silver. 


